View source for Nutria

{{Short description|Semi-aquatic rodent from South America}}
{{for|the color|Nutria (color)}}
{{redirect|Coypu|the boat|Coypu (dinghy)}}
{{use dmy dates|date=June 2024}}
{{Speciesbox
| name = Nutria
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name=iucn>{{cite iucn |author=Ojeda, R.|author2=Bidau, C.|author3=Emmons, L.| title = ''Myocastor coypus'' | volume = 2016 |errata=2017 | article-number = e.T14085A121734257 | year = 2016 | access-date = 12 March 2022}}</ref>
| fossil_range = {{Fossil range|Late Pliocene | Recent}}
| image = Nutria (Myocastor coypus).jpg
| image_caption = 
| display_parents = 3
| genus = Myocastor
| parent_authority = 
| species = coypus
| authority = ([[Juan Ignacio Molina|Molina]], 1782)
| range_map = Nutria.svg
| range_map_caption = The range of the Nutria <br />'''Regions'''{{Legend|#b69268|Extant (resident)}}{{Legend|#f03b20|Extant & Introduced (resident)}}'''Countries'''{{Legend|#fff7bc|Extant & Introduced (resident)}}{{Legend|#fee391|Extant (resident)}}{{Legend|#a8ddb5|Extant & Introduced}}
}}

The '''nutria''' ({{IPAc-en|ˈ|n|juː|t|r|i|ə}}) or '''coypu''' ({{IPAc-en|ˈ|k|ɔɪ|p|uː}}) ('''''Myocastor coypus''''')<ref name=iucn/><ref name=itis>{{cite web| title = ''Myocastor coypus''| url = https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=180402| website = ITIS| access-date = 23 September 2011| archive-date = 18 October 2011| archive-url = https://web.archive.org/web/20111018142751/http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=180402| url-status = live}}</ref> is a [[herbivore|herbivorous]],<ref>{{Cite web| url=http://animaldiversity.org/accounts/Myocastor_coypus/| title=Myocastor coypus (coypu)| website=Animal Diversity Web, Museum of Zoology| publisher=University of Michigan| date=1999| access-date=2017-08-25| archive-date=2017-08-25| archive-url=https://web.archive.org/web/20170825065014/http://animaldiversity.org/accounts/Myocastor_coypus/| url-status=live}}</ref> [[semiaquatic]] [[rodent]] from [[South America]].
Classified for a long time as the only member of the family Myocastoridae,<ref name="Woods1982">{{Cite book|last1=Woods |first1=C. A. | editor-last1=Mares| editor-first1=M. A.| editor-last2=Genoways| editor-first2=H. H.|title=Mammalian Biology in South America |publisher=University of Pittsburgh |year=1982 |pages=377–392 |chapter=The history and classification of South American Hystricognath rodents: reflections on the far away and long ago |location=Pittsburgh }}</ref> ''Myocastor'' has since been included within [[Echimyidae]], the family of the spiny rats.<ref name="Galewski2005">{{Cite journal|last1=Galewski|first1=Thomas|last2=Mauffrey|first2=Jean-François|last3=Leite|first3=Yuri L. R.|last4=Patton|first4=James L.|last5=Douzery|first5=Emmanuel J. P.|year=2005|title=Ecomorphological diversification among South American spiny rats (Rodentia; Echimyidae): a phylogenetic and chronological approach|journal=Molecular Phylogenetics and Evolution|volume=34|issue=3|pages=601–615|doi=10.1016/j.ympev.2004.11.015|pmid=15683932|bibcode=2005MolPE..34..601G }}</ref><ref name="Upham2012">{{Cite journal|last1=Upham|first1=Nathan S.|last2=Patterson|first2=Bruce D.|year=2012|title=Diversification and biogeography of the Neotropical caviomorph lineage Octodontoidea (Rodentia: Hystricognathi)|journal=Molecular Phylogenetics and Evolution|volume=63|issue=2|pages=417–429|doi=10.1016/j.ympev.2012.01.020|pmid=22327013|bibcode=2012MolPE..63..417U }}</ref><ref name="Fabre2017">{{Cite journal|last1=Fabre|first1=Pierre-Henri|last2=Upham|first2=Nathan S.|last3=Emmons|first3=Louise H.|last4=Justy|first4=Fabienne|last5=Leite|first5=Yuri L. R.|last6=Loss|first6=Ana Carolina|last7=Orlando|first7=Ludovic|last8=Tilak|first8=Marie-Ka|last9=Patterson|first9=Bruce D.|last10=Douzery|first10=Emmanuel J. P.|date=2017-03-01|title=Mitogenomic Phylogeny, Diversification, and Biogeography of South American Spiny Rats|journal=Molecular Biology and Evolution|volume=34|issue=3|pages=613–633|doi=10.1093/molbev/msw261|pmid=28025278|issn=0737-4038|doi-access=free}} {{free access}}</ref>
The nutria lives in burrows alongside stretches of water and feeds on river plant stems.<ref name="Taylor1997">{{Cite journal|last1=Taylor|first1=K.|last2=Grace|first2=J.|last3=Marx|first3=B.|date=May 1997|title=The effects of herbivory on neighbor interactions along a coastal marsh gradient|journal=American Journal of Botany|volume=84|issue=5|page=709|issn=0002-9122|pmid=21708623|doi=10.2307/2445907|jstor=2445907|bibcode=1997AmJB...84..709T }} {{free access}}</ref>

Originally native to subtropical and temperate South America, it was introduced to North America, Europe and Asia, primarily by [[fur farm]]ers.<ref name=APHIS>{{cite web | author1=LeBlanc, Dwight J. |date=1994 |url=http://www.ces.ncsu.edu/nreos/wild/pdf/wildlife/NUTRIA.PDF |title=Prevention and Control of Wildlife Damage – Nutria|archive-url=https://web.archive.org/web/20070203022247/http://www.ces.ncsu.edu/nreos/wild/pdf/wildlife/NUTRIA.PDF |archive-date=3 February 2007 |website=[[Animal and Plant Health Inspection Service]]}}</ref> Although it is still hunted and trapped for [[nutria fur|its fur]] in some regions, its destructive burrowing and feeding habits often bring it into conflict with humans, and it is considered an [[invasive species]] in the United States.<ref name= "WDFW">{{Cite web|url=https://wdfw.wa.gov/living/nutria.html|title=Living with Wildlife – Nutria|access-date=2019-03-22|archive-date=2019-03-22|archive-url=https://web.archive.org/web/20190322175916/https://wdfw.wa.gov/living/nutria.html|url-status=live}}</ref> Nutrias also transmit various diseases to humans and animals, mainly through water contamination.<ref name="Ca.Gov">{{Cite web |last=Ca.Gov |first=Department of Fish and Wildlife |title=California's Invaders:Nutria |url=https://wildlife.ca.gov/Conservation/Invasives/Species/Nutria |access-date=2022-05-08 |archive-date=2022-04-30 |archive-url=https://web.archive.org/web/20220430140904/https://wildlife.ca.gov/Conservation/Invasives/Species/Nutria |url-status=live }}</ref>

== Etymology ==
The genus name ''Myocastor'' derives from the two [[Ancient Greek]] words {{wikt-lang|grc|μῦς}} ({{grc-transl|μῦς}}) 'rat, mouse', and {{wikt-lang|grc|κάστωρ}} ({{grc-transl|κάστωρ}}) 'beaver'.<ref>{{Cite book|title=Abrégé du dictionnaire grec français|last=Bailly|first=Anatole|year=1981|publisher=Hachette|isbn=978-2-01-003528-9|location=Paris|oclc=461974285}}</ref><ref>{{Cite web|url=http://www.tabularium.be/bailly/|title=Greek-French dictionary online|last=Bailly|first=Anatole|website=www.tabularium.be|access-date=2017-01-24|archive-date=2022-03-18|archive-url=https://web.archive.org/web/20220318000653/http://www.tabularium.be/bailly/|url-status=live}}</ref><ref>[http://www.nutria.com/site5.php Nutria Biology] {{Webarchive|url=https://web.archive.org/web/20131022202545/http://www.nutria.com/site5.php |date=2013-10-22 }}. Nutria.com. 2007. Retrieved on September 5, 2007.</ref> Therefore, the name ''Myocastor'' literally means 'mouse-beaver'.

Two names are commonly used in [[English language|English]] for ''Myocastor coypus''. The name ''nutria'' (from the Spanish word ''nutria'' 'otter') is generally used in North America, Asia, and throughout [[Post-Soviet states|countries of the former Soviet Union]]; however, in most [[Spanish language|Spanish]]-speaking countries, the word ''nutria'' refers primarily to the [[otter]]. To avoid this ambiguity, the name ''coypu'' or ''coipo'' (derived from [[Mapudungun language|Mapudungun]]) is used in South America, Britain and other parts of Europe.<ref name=USGS2>{{cite web|author1=Carter, Jacoby|url=https://www.nwrc.usgs.gov/special/nutria/samerica.htm|title=Worldwide Distribution, Spread of, and Efforts to Eradicate the Nutria (''Myocastor coypus'') – South America|website=[[United States Geological Survey]]|date=29 January 2007|access-date=4 September 2007|archive-date=18 February 2017|archive-url=https://web.archive.org/web/20170218014721/http://www.nwrc.usgs.gov/special/nutria/samerica.htm|url-status=live}}</ref> In France, the nutria is known as a ''ragondin''. In Dutch, it is known as ''beverrat'' 'beaver-rat'. In German, it is known as ''Nutria'', ''Biberratte'' 'beaver-rat', or ''Sumpfbiber'' 'swamp-beaver'. In Italy, instead, the popular name is, as in North America and Asia, ''nutria'', but it is also called ''castorino'' 'little [[beaver]]', by which its fur is known in Italy. In Swedish, the animal is known as ''sumpbäver'' 'marsh/swamp-beaver'. In Brazil, the animal is known as ''ratão-do-banhado'' 'big swamp-rat', ''nútria'', or ''caxingui'' (the last from [[Tupi language|Tupi]]).

== Taxonomy ==
[[File:RagondinCrâne.jpg|thumb|right|Skull]]
The nutria was first described by [[Juan Ignacio Molina]] in 1782 as ''Mus coypus'', a member of the [[mouse]] genus.<ref name=mammalspecies>{{cite journal |last1=Woods |first1=Charles A. |last2=Contreras |first2=Luis |last3=Willner-Chapman |first3=Gale |last4=Whidden |first4=Howard P. |title=''Myocastor coypus'' |journal=Mammalian Species |date=1992 |issue=398 |pages=1–8 |doi=10.2307/3504182|jstor=3504182 |url=http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-398-01-0001.pdf|archive-url=https://web.archive.org/web/20171008180721/http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-398-01-0001.pdf |archive-date=2017-10-08 }}</ref> The genus ''Myocastor'' was assigned in 1792 by [[Robert Kerr (writer)|Robert Kerr]].<ref name="ITIS2">{{cite web|url=https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=180401|author=ITIS Report|title=ITIS Standard Report: Myocastor|access-date=September 5, 2007|archive-date=December 1, 2007|archive-url=https://web.archive.org/web/20071201130608/http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=180401|url-status=live}}</ref> [[Étienne Geoffroy Saint-Hilaire|Geoffroy Saint-Hilaire]], independently of Kerr, named the species ''Myopotamus coypus'',<ref>{{cite web
   |url=https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=203538
   |author=ITIS Report
   |title=ITIS Standard Report: Myopotamus
   |access-date=December 19, 2007
   |archive-date=October 23, 2011
   |archive-url=https://web.archive.org/web/20111023070408/http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=203538
   |url-status=live
   }}</ref> and it is occasionally referred to by this name.

Four subspecies are generally recognized:<ref name=mammalspecies />
*''M. c. bonariensis'': northern Argentina, Bolivia, Paraguay, Uruguay, southern Brazil (RS, SC, PR, and SP)
*''M. c. coypus'': central Chile, Bolivia
*''M. c. melanops'': [[Chiloé Island]]
*''M. c. santacruzae'': [[Patagonia]]

''M. c. bonariensis'', the subspecies present in the northernmost (subtropical) part of the nutria's range, is believed to be the type of nutria most commonly introduced to other continents.<ref name=USGS2 />
<gallery mode = packed heights = 160px>
Coypu (Myocastor coypus coypus) feeding Tricao.jpg|''M. c. coypus'' feeding; in Chile
Coypu (Myocastor coypus coypus) swimming Tricao.jpg|The species is native to South America
</gallery>

== Phylogeny ==
Comparison of DNA and protein sequences showed that the genus ''Myocastor'' is the sister group to the genus ''Callistomys'' (painted tree-rats).<ref name="Loss2014"/><ref name="Fabre2017"/> In turn, these two taxa share evolutionary affinities with other [[Myocastorini]] genera: ''Proechimys'' and ''Hoplomys'' (armored rats) on the one hand, and ''Thrichomys'' on the other hand.

{{cladogram
   |title=Genus-level cladogram of the Myocastorini.
   |caption=The cladogram has been reconstructed from mitochondrial and nuclear DNA characters.<ref name="Galewski2005"/><ref name="Upham2012"/><ref name="Fabre2013">{{Cite journal|last1=Fabre|first1=Pierre-Henri|last2=Galewski|first2=Thomas|last3=Tilak|first3=Marie-ka|last4=Douzery|first4=Emmanuel J. P.|date=2013-03-01|url=http://macroecointern.dk/pdf-reprints/Fabre_ZS_2013.pdf|title=Diversification of South American spiny rats (Echimyidae): a multigene phylogenetic approach|journal=Zoologica Scripta|language=en|volume=42|issue=2|pages=117–134|doi=10.1111/j.1463-6409.2012.00572.x|s2cid=83639441|issn=1463-6409|access-date=2019-11-18|archive-date=2019-11-18|archive-url=https://web.archive.org/web/20191118184152/http://macroecointern.dk/pdf-reprints/Fabre_ZS_2013.pdf|url-status=live}}</ref><ref name="Loss2014">{{Cite journal|last1=Loss|first1=Ana|last2=Moura|first2=Raquel T.|last3=Leite|first3=Yuri L. R.|date=2014|title=Unexpected phylogenetic relationships of the painted tree rat ''Callistomys pictus'' (Rodentia: Echimyidae)|url=http://www.naturezaonline.com.br/natureza/conteudo/pdf/05_LossACetal_132-136.pdf|journal=Natureza on Line|volume=12|pages=132–136|access-date=2017-10-08|archive-date=2021-06-23|archive-url=https://web.archive.org/web/20210623231029/http://www.naturezaonline.com.br/natureza/conteudo/pdf/05_LossACetal_132-136.pdf|url-status=live}}</ref><ref name="Fabre2014">{{Cite journal|last1=Fabre|first1=Pierre-Henri|last2=Vilstrup|first2=Julia T.|last3=Raghavan|first3=Maanasa|last4=Der Sarkissian|first4=Clio|last5=Willerslev|first5=Eske|last6=Douzery|first6=Emmanuel J. P.|last7=Orlando|first7=Ludovic|date=2014-07-01|title=Rodents of the Caribbean: origin and diversification of hutias unravelled by next-generation museomics|journal=Biology Letters|language=en|volume=10|issue=7|article-number=20140266|doi=10.1098/rsbl.2014.0266|pmid=25115033|issn=1744-9561|pmc=4126619}}</ref><ref name="Upham2015">{{Cite book|title=Biology of caviomorph rodents: diversity and evolution|last1=Upham|first1=Nathan S.|last2=Patterson|first2=Bruce D.|publisher=SAREM Series A, Mammalogical Research – Sociedad Argentina para el Estudio de los Mamíferos|year=2015|editor-last1=Vassallo|editor-first1=Aldo Ivan|location=Buenos Aires|pages=63–120 |chapter-url= https://www.researchgate.net/publication/282577627 |chapter=Evolution of Caviomorph rodents: a complete phylogeny and timetree for living genera|editor-last2=Antenucci|editor-first2=Daniel}}</ref><ref name="Fabre2017"/>
   |align=center
   |clades={{Cladogram of Myocastorini genera}}
}}

== Appearance ==
[[Image:Nutria-orange.JPG|thumb|right|Large orange teeth are clearly visible on this nutria]]
The nutria somewhat resembles a very large [[rat]], or a [[beaver]] with a small, long and skinny hairless tail. Adults are typically {{convert|4|-|9|kg|lb|0|abbr=on}} in weight, and {{convert|40|-|60|cm|abbr=on}} in body length, with a {{convert|30|to|45|cm|in|0|abbr=on}} tail. It is possible for nutrias to weigh up to {{convert|16|to|17|kg|lb|0|abbr=on}}, although adults usually average {{convert|4.5|to|7|kg|lb|0|abbr=on}}.<ref>{{Cite journal | doi=10.1016/0021-9975(67)90014-X| title=Foot-and-mouth disease in Myocastor coypus| year=1967| last1=Capel-Edwards| first1=Maureen| journal=Journal of Comparative Pathology| volume=77| issue=2| pages=217–221| pmid=4291914}}</ref><ref>{{Cite journal |doi = 10.1111/j.1600-0587.1990.tb00594.x|title = Response by coypus to catastrophic events of cold and flooding|year = 1990|last1 = Doncaster|first1 = C. P.|last2 = Micol|first2 = T.|journal = Ecography|volume = 13|issue = 2|pages = 98–104| bibcode=1990Ecogr..13...98D }}</ref><ref>{{Cite journal | doi=10.1002/ar.1091300304| title=The genital systems of nutria(Myocastor coypus)| year=1958| last1=Hillemann| first1=Howard H.| last2=Gaynor| first2=Alta I.| last3=Stanley| first3=Hugh P.| journal=The Anatomical Record| volume=130| issue=3| pages=515–531| pmid=13559732| s2cid=12757377}}</ref> Nutrias have three sets of fur. The guard hairs on the outer coat are three inches long.<ref name="trappers-2021">{{Cite web |date=2012–2021 |title=national trappers |url=https://www.nationaltrappers.com/nutria.html |access-date=2022-05-08 |archive-date=2022-07-02 |archive-url=https://web.archive.org/web/20220702195306/https://www.nationaltrappers.com/nutria.html |url-status=live }}</ref> They have coarse, darkish brown midlayer fur with soft dense grey under fur, also called the nutria. Three distinguishing features are a white patch on the muzzle, webbed hind feet, and large, bright orange-yellow [[incisor]]s.<ref>{{cite web|url=https://eol.org/pages/328471|title=Myocastor coypus (Molina 1782) - Encyclopedia of Life|website=eol.org|access-date=2019-03-22|archive-date=2019-05-31|archive-url=https://web.archive.org/web/20190531011408/https://eol.org/pages/328471|url-status=live}}</ref> They have approximately 20 teeth with four large incisors that grow during the entirety of their lives.<ref>{{Cite journal |last=Valentin |first=Fischer |date=March 17, 2022 |title=Species-specific enamel differences in hardness and abrasion resistance between the permanent incisors of cattle and ever-growing incisors of nutria |journal=PLOS ONE|volume=17 |issue=3 |article-number=e0265237 |doi=10.1371/journal.pone.0265237 |pmid=35298510 |pmc=8929658 |doi-access=free }}</ref> The orange discoloration is due to pigment staining from the mineral iron in the tooth enamel.  Nutrias have prominent four inch long whiskers on each side of their muzzle or cheek area. The mammary glands and [[teat]]s of female nutrias are high on her flanks, to allow their young to feed while the female is in the water. There is no visible distinction between male and female nutria. Both are similar in coloring and weight.

A nutria is often mistaken for a [[muskrat]] (''Ondatra zibethicus''), another widely dispersed, semiaquatic rodent that occupies the same wetland habitats. The muskrat, however, is smaller and more tolerant of cold climates, and has a laterally flattened tail it uses to assist in swimming, whereas the tail of a nutria is round. It can also be mistaken for a small beaver, as beavers and nutrias have very similar anatomies and habitats. However, beavers' tails are flat and paddle-like, as opposed to the round tails of nutria.<ref name="Beaver">{{cite web |title=Species Profile: Castor canadensis – North American Beaver |url=https://bellavistapoa.com/2019/02/05/species-profile-castor-canadensis-north-american-beaver/ |website=Bella Vista Property Owners Association |date=5 February 2019 |access-date=6 October 2019 |location=Bella Vista, Arkansas |quote=They could be mistaken for a nutria, but nutrias do not have the large flat paddle-shaped tail like beavers. |archive-date=6 October 2019 |archive-url=https://web.archive.org/web/20191006141355/https://bellavistapoa.com/2019/02/05/species-profile-castor-canadensis-north-american-beaver/ |url-status=live }}</ref>

==Life history==
[[File:Nutria population in Weilerswist, Germany low res.ogv|right|thumb|Nutria behaviours<br />[[:File:Nutria population in Weilerswist, Germany.ogg|view in Full HD]]]]

Nutrias can live up to six years in captivity, but individuals rarely live past three years old in the wild. According to one study, 80% of nutrias die within the first year, and less than 15% of a wild population is over three years old.<ref name="nolfo">{{Cite journal|title = Nutria Survivorship, Movement Patterns, and Home Ranges|date = September 2009 |url = https://www.researchgate.net/publication/232684874 |last = Nolfo-Clements|first = Lauren E.|journal = Southeastern Naturalist|issn = 1938-5412|issue = 3|volume = 8|pages = 399–410|doi=10.1656/058.008.0303|s2cid = 86801126 }}</ref> A nutria is considered to have reached old age at four years old. Male nutrias reach sexual maturity as early as four months, and females as early as three months; however, both can have a prolonged adolescence, up to the age of nine months. Once a female is pregnant, [[gestation]] lasts 130 days, and she may give birth to as few as one or as many as 13 offspring. The average nutria reproduction is four offspring. Female nutrias will mate within two days after offspring are born. The years of reproduction cycle by litter size. Year one might be large, year two litter size will be smaller and year three the litter size will be another larger size. Females can only produce six litters in her life, rarely seven litters.<ref name="trappers-2021"/> A female on average will have two litters a year.

Nutrias generally line nursery nests with grasses and soft reeds. Baby nutrias are [[precocial]], born fully furred and with open eyes; they can eat vegetation and swim with their parents within hours of birth. A female nutria can become pregnant again the day after she gives birth to her young. If timed properly, a female can become pregnant three times within a year. Newborn nutrias nurse for seven to eight weeks, after which they leave their mothers.<ref name="biology">{{Cite web|url = http://www.nutria.com/site5.php|title = Biology|access-date = 2 March 2014|publisher = [[Louisiana Department of Wildlife and Fisheries]]|website = Nutria|url-status = live|archive-date = 22 October 2013|archive-url = https://web.archive.org/web/20131022202545/http://www.nutria.com/site5.php}}</ref> Nutrias have been known to be territorial and aggressive when caught or cornered. They will bite and attack humans and dogs when threatened.<ref>{{Cite web |last=species and habitats |first=Washington Department of Fish and Wildlife |date=April 22, 2022 |title=Nutria Conflict |url=https://wdfw.wa.gov/species-habitats/invasive/myocastor-coypus#conflict |access-date=2022-04-22 |archive-date=2022-03-31 |archive-url=https://web.archive.org/web/20220331081801/https://wdfw.wa.gov/species-habitats/invasive/myocastor-coypus#conflict |url-status=live }}</ref> Nutrias are mainly crepuscular or nocturnal, with most activity occurring around dusk and sunset with highest activity around midnight. When food is scarce, nutrias will forage during the day. When food is plentiful, nutrias will rest and groom during the day.<ref>{{Cite web |last=researched based wildlife damage management information |first=Internet center for wildlife damage management |date=April 22, 2022 |title=Nutria Biology |url=https://icwdm.org/species/rodents/nutria/nutria-biology/. |access-date=September 29, 2022 |archive-date=September 29, 2022 |archive-url=https://web.archive.org/web/20220929125147/https://icwdm.org/species/rodents/nutria/nutria-biology/ |url-status=live }}</ref>

== Distribution ==
[[File:Nutria (Coypu) occurrence records from 1980 to 2018 in Europe.jpg|thumb|Nutria occurrence records from 1980 to 2018 in Europe.<ref>{{cite journal |last1=Schertler |first1=Anna |last2=Rabitsch |first2=Wolfgang |last3=Moser |first3=Dietmar |last4=Wessely |first4=Johannes |last5=Essl |first5=Franz |title=The potential current distribution of the coypu (Myocastor coypus) in Europe and climate change induced shifts in the near future |journal=NeoBiota |date=17 July 2020 |volume=58 |pages=129–160 |doi=10.3897/neobiota.58.33118 |s2cid=221089826 |url=https://neobiota.pensoft.net/article/33118 |access-date=15 April 2023 |language=en |issn=1314-2488 |doi-access=free |bibcode=2020NeoBi..58..129S |archive-date=15 April 2023 |archive-url=https://web.archive.org/web/20230415191223/https://neobiota.pensoft.net/article/33118 |url-status=live }}</ref>]]

Native to subtropical and temperate South America, its range includes Chile, Argentina, Uruguay, Paraguay and the southern parts of Brazil and Bolivia. It has been introduced to North America, Europe and Asia, primarily by fur ranchers.
The distribution of nutrias outside South America tends to contract or expand with successive cold or mild winters. During cold winters, nutrias often suffer [[frostbite]] on their tails, leading to infection or death.  As a result, populations of nutria often contract and even become locally or regionally [[extinct]] as in the [[Scandinavia]]n countries and such [[U.S. states]] as Idaho, Montana, and Nebraska during the 1980s.<ref>Carter, Jacoby and Billy P. Leonard  (Spring, 2002.) "A Review of the Literature on the Worldwide Distribution, Spread of, and Efforts to Eradicate the Coypu (Myocastor coypus)" ''Wildlife Society Bulletin'' 30(1): 162–175.</ref>  During mild winters, their ranges tend to expand northward.  For example, in recent years, range expansions have been noted in Washington and Oregon,<ref>{{cite report |url=http://pdxscholar.library.pdx.edu/centerforlakes_pub/24/ |title=Report on Nutria Management and Research in the Pacific Northwest |last1=Sheffels |first1=Trevor Robert |last2=Sytsma |first2=Mark |date=December 2007 |publisher=Center for Lakes and Reservoirs Publications and Presentations, Portland State University |access-date=2016-09-24 |archive-date=2016-09-27 |archive-url=https://web.archive.org/web/20160927033559/http://pdxscholar.library.pdx.edu/centerforlakes_pub/24/ |url-status=live }}</ref> as well as Delaware.<ref>{{Citation |last=Montgomery |first=Jeff |title=Invasive nutria found in Kent County |url=http://www.delawareonline.com/article/20120119/NEWS08/201190343/-1/NLETTER01/Invasive-nutria-found-in-Kent-County |newspaper=[[The News Journal]] |publication-date=19 Jan 2012 |year=2012 |at=delawareonline |quote='It was a surprise, frankly,' Steve Kendrot, a U.S. Department of Agriculture wildlife services program manager, said Wednesday. 'We didn't expect to find anything that far up.' |access-date=19 Jan 2012 |archive-date=28 July 2014 |archive-url=https://web.archive.org/web/20140728024112/http://www.delawareonline.com/article/20120119/NEWS08/201190343/-1/NLETTER01/Invasive-nutria-found-in-Kent-County |url-status=live }}</ref>

According to the [[U.S. Geological Survey]], nutrias were first introduced to the United States in [[California]], in 1899 by [[William Franklin Frakes]]. {{As of|2024}}, they had spread to the San Francisco Bay Area, where their digging threatened [[Levee|storm levees]], and the [[California Department of Fish and Wildlife]] had an active eradication program.<ref>{{Cite news |last=Graff |first=Amy |date=4 October 2024 |title=Invasive 20-pound rodents continue to spread in the Bay Area |url=https://www.sfgate.com/local/article/nutria-spread-in-bay-area-19811411.php |work=[[SFGate]]}}</ref><ref>{{Cite web |title=California's Invaders: Nutria |url=https://wildlife.ca.gov/Conservation/Invasives/Species/Nutria |access-date=2024-10-05 |website=[[California Department of Fish and Wildlife]]}}</ref>

They were first brought to [[Louisiana]] in the early 1930s for the fur industry, and the population was kept in check, or at a small population size, because of trapping pressure from the fur traders.<ref name="USGS2" /> The earliest account of nutrias spreading freely into Louisiana wetlands from their enclosures was in the early 1940s; a hurricane hit the Louisiana coast for which many people were unprepared, and the storm destroyed the enclosures, enabling the nutrias to escape into the wild.<ref name="USGS2" /> According to the Louisiana Department of Wildlife and Fisheries, nutrias were also transplanted from [[Port Arthur, Texas]], to the [[Mississippi River]] in 1941 and then spread due to a hurricane later that year.<ref>{{cite web |date=2007 |title=History; Nutria Population Dynamics – A Timeline |url=http://www.nutria.com/site2.php |access-date=10 October 2011 |website=Nutria.com |publisher=Louisiana Department of Wildlife and Fisheries |archive-date=18 September 2011 |archive-url=https://web.archive.org/web/20110918081809/http://www.nutria.com/site2.php |url-status=live }}</ref>

==Habitat and feeding==
[[File:A coypu or nutria in a canal in Milan.webm|thumb|A nutria in a canal in Milan]]

Besides breeding quickly, each nutria consumes large amounts of aquatic vegetation.<ref>{{Cite web|url=https://animaldiversity.org/accounts/Myocastor_coypus/|title=Myocastor coypus (coypu)|first=Guillermo|last=D'Elia|website=Animal Diversity Web|access-date=2023-01-11|archive-date=2023-02-17|archive-url=https://web.archive.org/web/20230217101419/http://animaldiversity.org/accounts/Myocastor_coypus/|url-status=live}}</ref> An individual consumes about 25% of its body weight daily, and feeds year-round.<ref name="biology"/><ref name="mcfalls"/>  Being one of the world's larger extant rodents, a mature, healthy nutria averages {{convert|5.4|kg|lboz|0|abbr=on}} in weight, but they can reach as much as {{convert|10|kg|lb|0|abbr=on}}.<ref name="icwdm">{{Cite web|url = http://icwdm.org/handbook/rodents/nutria.asp|title = Nutria|year = 1994|access-date = 2 March 2014|publisher = Internet Center for Wildlife Damage Management|editor1 = Hygnstrom, Scott E.|editor2 = Timm, Robert M.|editor3 = Larson, Gary E.|archive-date = 7 September 2013|archive-url = https://web.archive.org/web/20130907061545/http://icwdm.org/Handbook/rodents/Nutria.asp}}</ref><ref>{{Cite web | url = http://www.zoobarcelona.cat/en/know-the-zoo/animal-files/mammals/detail/animal/coypu/ | title = Detail (Coypu) | access-date = 2 March 2014 | website = [[Barcelona Zoo]] | publisher = Barcelona City Council | archive-date = 26 September 2013 | archive-url = https://web.archive.org/web/20130926064335/http://www.zoobarcelona.cat/en/know-the-zoo/animal-files/mammals/detail/animal/coypu/ | location = Spain }}</ref> They eat the base of the above-ground stems of plants, and often dig through soil for roots and [[rhizomes]] to eat.<ref name="carter"/> Nutrias eat parts and whole plants, and go after roots, rhizomes, tubers and black willow tree bark in the winter. Their creation of "eat-outs", areas where a majority of the above- and below-ground biomass has been removed, produces patches in the environment, which in turn disrupts the habitat for other animals and humans dependent on wetlands and marshes.<ref name="ford">{{cite journal |last1=Ford |first1=Mark A. |last2=Grace |first2=James B. |title=Effects of vertebrate herbivores on soil processes, plant biomass, litter accumulation and soil elevation changes in a coastal marsh |journal=Journal of Ecology |date=1998 |volume=86 |issue=6 |pages=974–982 |doi=10.1046/j.1365-2745.1998.00314.x|doi-access=free |bibcode=1998JEcol..86..974F }}</ref> Nutrias eat the following plant varieties: [[Typha|cattail]], [[Juncaceae|rushes]], [[Reed (plant)|reeds]], [[sagittaria|arrowheads]], [[Cyperus|flatsedges]], and [[Spartina|cordgrasses]]. Commercial crops that nutrias also eat are lawn grasses, alfalfa, corn, rice, and sugarcane.<ref name="trappers-2021"/>

Nutrias are found most commonly in freshwater marshes and wetlands, but also inhabit brackish marshes and rarely salt marshes.<ref name="cncp"/><ref name="meat">{{cite journal |last1=Lyon |first1=W. J. |last2=Milliet |first2=J. B. |title=Microbial Flora Associated with Louisiana Processed Frozen and Fresh Nutria (''Myocastor coypus'') Carcasses |journal=Journal of Food Science |date=2000 |volume=65 |issue=6 |pages=1041–1045 |doi=10.1111/j.1365-2621.2000.tb09414.x}}</ref> They either construct their own burrows, or occupy burrows abandoned by beaver, muskrats, or other animals.<ref name="WDFW"/> They are also capable of constructing floating rafts out of vegetation.<ref name="WDFW"/> Nutrias live in partially underwater dens. The main chamber is not submerged underground. Nutrias are considered to be a species that lives in colonies. One male will share a den with three or four females and their offspring. Nutrias use "feeding platforms" which are constructed in the water from cut pieces of vegetation supported by a structure like a log or branches. Muskrat dens and beaver lodges are also often used as feeding platforms.<ref name="trappers-2021"/>

==Commercial use and issues==
[[File:Ratao do banhado 1 REFON.jpg|thumb|right|''Myocastor coypus'']]

=== Farming and the fur trade ===
Local extinction in their native range due to [[overharvesting]] led to the development of nutria fur farms in the late 19th and early 20th centuries. The first farms were in Argentina and then later in Europe, North America, and Asia. These farms have generally not been successful long-term investments, and farmed nutrias often are released or escape as operations become unprofitable. The first attempt at nutria farming was in France in the early 1880s, but it was not much of a success.<ref name="NWRC2000">National Wetlands Research Center (June 2000), ''Nutria, Eating Louisiana's Coast'', United States Geological Survey</ref> The first efficient and extensive nutria farms were located in South America in the 1920s.<ref name="NWRC2000" /> The South American farms were very successful, and led to the growth of similar farms in North America and Europe. Nutrias from these farms often escaped, or were deliberately released into the wild to provide a game animal or to remove aquatic vegetation.<ref>Carter, Jacoby, and Billy P. Leonard (2002). "A Review of the Literature on the Worldwide Distribution, Spread Of, and Efforts to Eradicate the Coypu (Myocastor coypus)." N.p., Web. 2 Nov. 2015.</ref>

Nutrias were introduced to the Louisiana ecosystem in the 1930s, when they escaped from fur farms that had imported them from South America. Nutrias were released into the wild by at least one Louisiana nutria farmer in 1933 and these releases were followed by [[Edward Avery McIlhenny|E. A. McIlhenny]] who released his entire stock in 1945 on Avery Island.<ref>{{Cite report |author=<!--Staff writer(s); no by-line.--> |date=June 2000 |title=Nutria, Eating Louisiana's Coast |url=https://www.nwrc.usgs.gov/factshts/020-00.pdf |publisher=U.S. Geological Survey/National Wetlands Research Center |docket=USGS FS-020-00 |access-date=28 March 2016 |archive-date=5 March 2016 |archive-url=https://web.archive.org/web/20160305011802/http://www.nwrc.usgs.gov/factshts/020-00.pdf |url-status=live }}</ref> In 1940, some of the nutrias escaped during a hurricane and quickly populated coastal marshes, inland swamps, and other wetland areas.<ref name="M'sieu">{{cite journal|author1=Bernard, Shane K.|title=M'sieu Ned's Rat? Reconsidering the Origin of Nutria in Louisiana|publisher=The E. A. McIlhenny Collection, Louisiana Historical Association|location=Avery Island, Louisiana|date=November 2015|journal=Louisiana History: The Journal of the Louisiana Historical Association|volume=43|issue=3|jstor=4233862}}</ref> From Louisiana, nutrias have spread across the Southern United States, wreaking havoc on marshlands.

Following a decline in demand for nutria fur, nutrias have since become pests in many areas, destroying aquatic vegetation, marshes, and [[irrigation]] systems, and chewing through man-made items such as tires and wooden house panelling in Louisiana, eroding river banks, and displacing native animals. Damage in Louisiana has been sufficiently severe since the 1950s to warrant legislative attention; in 1958, the first bounty was placed on nutria, though this effort was not funded.<ref name="Scarborough2007">{{citation|title = Nutria Harvest Distribution 2006-2007 and a Survey of Nutria Herbivory Damage in Coastal Louisiana in 2007|url = http://www.nutria.com/uploads/0607Finalreport.pdf|last1 = Scarborough|first1 = Janet|last2 = Mouton, Edmond|date = 30 June 2007|url-status = live|archive-date = 7 January 2009|archive-url = https://web.archive.org/web/20090107004406/http://www.nutria.com/uploads/0607Finalreport.pdf}}</ref>{{rp|3}}  By the early 2000s, the Coastwide Nutria Control Program was established, which began paying bounties for nutrias killed in 2002.<ref name="Scarborough2007" />{{Rp|19–20}}  In the [[Chesapeake Bay]] region in [[Maryland]], where they were introduced in the 1940s, nutrias are believed to have destroyed {{convert|7000|to|8000|acre|ha|order=flip}} of marshland in the [[Blackwater National Wildlife Refuge]] by eating the roots of marshland plants.<ref name="NWF"/>  In response, by 2003, a multimillion-dollar eradication program was underway.<ref name="NWF">[https://www.nwf.org/News-and-Magazines/National-Wildlife/Animals/Archives/2003/A-Plague-of-Aliens.aspx "A Plague of Aliens"] {{Webarchive|url=https://web.archive.org/web/20170813014336/https://www.nwf.org/News-and-Magazines/National-Wildlife/Animals/Archives/2003/A-Plague-of-Aliens.aspx |date=2017-08-13 }} Feb/Mar 2003 edition of National Wildlife magazine, published by the [[National Wildlife Federation]], article by Laura Tangley; accessed online December 8, 2006.</ref>

In the United Kingdom, nutrias were introduced to [[East Anglia]], for fur, in 1929; many escaped and damaged the drainage works, and a concerted programme by [[Ministry of Agriculture, Fisheries and Food (United Kingdom)|MAFF]] eradicated them by 1989.<ref>{{cite journal|last=Gosling|first=Morris|date=4 March 1989|title=Extinction to Order|journal=[[New Scientist]]|volume=121|issue=1564|pages=44–49}}</ref>

=== Food products ===
In 1997 and 1998, Louisiana attempted to encourage the public to consume nutria meat. Nutria meat is leaner with a lower fat content and lower in cholesterol compared to ground beef.<ref>{{Cite web |last=Randall |first=Morgan |title=Nutria a la' Orange |date=30 August 2019 |url=https://64parishes.org/nutria-a-lorange |access-date=March 31, 2022 |archive-date=11 February 2022 |archive-url=https://web.archive.org/web/20220211050917/https://64parishes.org/nutria-a-lorange |url-status=live }}</ref> In an effort to encourage Louisianians to eat nutria, several recipes were distributed to locals and published on the internet.<ref>{{Cite web |last=Parola |first=Philippe |date=March 31, 2022 |title=If you can't beat em' eat em' |url=http://www.cantbeatemeatem.us/nutria.html |access-date=May 8, 2022 |archive-date=April 1, 2022 |archive-url=https://web.archive.org/web/20220401091524/http://www.cantbeatemeatem.us/nutria.html }}</ref> People in poor and rural Louisiana have trapped and consumed nutria meat for decades.

A small number of game meat websites on the internet sell nutria meat for consumption. In Kyrgyzstan and Uzbekistan, nutrias (Russian and local languages Нутрия) are farmed on private plots and sold in local markets as a poor man's meat.<ref name="Hot rat is so hot right now: Moscow falls for the rodent burger">{{Cite news|url=https://www.theguardian.com/world/2016/nov/18/hot-rat-is-so-hot-right-now-moscow-falls-for-the-rodent-burger|title=Hot rat is so hot right now: Moscow falls for the rodent burger|last=Walker|first=Shaun|date=2016-11-18|work=The Guardian|access-date=2017-07-19|language=en-GB|issn=0261-3077|archive-date=2017-07-04|archive-url=https://web.archive.org/web/20170704235901/https://www.theguardian.com/world/2016/nov/18/hot-rat-is-so-hot-right-now-moscow-falls-for-the-rodent-burger|url-status=live}}</ref> As of 2016, however, the meat is used successfully in Moscow restaurant Krasnodar Bistro, as part of the growing Russian [[localvore]] movement and as a '[[foodie]]' craze.<ref name="Hot rat is so hot right now: Moscow falls for the rodent burger"/> It appears on the menu as a burger, hotdog, dumplings, or wrapped in cabbage leaves, with the flavour being somewhere between turkey and pork.<ref>{{cite news |url=http://www.thejakartapost.com/life/2016/11/24/rats-rodent-burger-now-the-latest-food-craze-in-moscow.html |title=Rats! Rodent burger now the latest food craze in Moscow |date=24 November 2016 |work=The Straits Times |publisher=The Jakarta Post |access-date=24 November 2016 |archive-date=24 November 2016 |archive-url=https://web.archive.org/web/20161124160712/http://www.thejakartapost.com/life/2016/11/24/rats-rodent-burger-now-the-latest-food-craze-in-moscow.html |url-status=live }}</ref>

A claimed environmentally sound solution is the use of nutria meat to make dog food treats.<ref name="Dodge">{{cite news |last1=Dodge |first1=Victoria |title=A rodent-like pest destroying the Louisiana coast finds new enemy in dog treat business |newspaper=[[Lafayette Daily Advertiser]] |agency=[[USA Today]] |url=https://www.yahoo.com/news/rodent-pest-destroying-louisiana-coast-113141933.html |access-date=September 7, 2019 |archive-date=December 24, 2019 |archive-url=https://web.archive.org/web/20191224001516/https://www.yahoo.com/news/rodent-pest-destroying-louisiana-coast-113141933.html |url-status=live }}</ref> Marsh Dog, a US company based in Baton Rouge, Louisiana, received a grant from the Barataria-Terrebonne National Estuary Program to establish a company that uses nutria meat for dog food products.<ref>{{Cite web |last=Guidry |first=Chas |date=19 Jul 2011 |title=Bill continues state's nutria-control program |url=http://www.dailycomet.com/article/20110719/ARTICLES/110719361/1026/sitemaps04?p=1&tc=pg |archive-url=https://web.archive.org/web/20160803053718/http://www.dailycomet.com/article/20110719/ARTICLES/110719361/1026/sitemaps04?p=1&tc=pg |archive-date=2016-08-03 |access-date=2017-07-19 |website=Daily Comet |language=en |location=Thibodaux, LA}}</ref> In 2012, the Louisiana Wildlife Federation recognized Marsh Dog with "Business Conservationist of the Year" award for finding a use for this eco-sustainable protein.<ref>{{Cite web|url=http://www.lawildlifefed.org/content.cfm?new=413&id=178|title=Louisiana Wildlife Federation|website=www.lawildlifefed.org|language=en|access-date=2017-07-19|archive-url=https://web.archive.org/web/20160729140400/http://www.lawildlifefed.org/content.cfm?new=413&id=178|archive-date=2016-07-29}}</ref>

== Ecological impacts ==
{{Globalize|section|US|date=April 2025|reason=Missing info on role as a native species in South American ecosystems}}
=== Herbivory and habitat degradation ===
[[File:Zoo, Zagreb - nutrija (04.2012).JPG|thumb|right|Zoo animal on logs]]

Nutria herbivory "severely reduces overall wetland biomass and can lead to the conversion of wetland to open water."<ref name="mcfalls">{{Cite journal |url= https://www.researchgate.net/publication/228478066 |title = Hurricanes, floods, levees, and nutria: vegetation responses to interacting disturbance and fertility regimes with implications for coastal wetland restoration|date = September 2010|last1 = McFalls|first1 = Tiffany B.|last2 = Keddy|first2 = Paul A.|last3 = Campbell|first3 = Daniel|last4 = Shaffer|first4 = Gary|display-authors = 1|issue = 5|volume = 26|pages = 901–911|doi = 10.2112/JCOASTRES-D-09-00037.1|journal = Journal of Coastal Research|s2cid = 55697728|issn = 1551-5036}}</ref> Unlike other common disturbances in marshlands, such as fire and tropical storms, which are a once- or few-times-a-year occurrence, nutrias feed year round, so their effects on the marsh are constant. Also, nutrias are typically more destructive in the winter than in the growing season, due largely to the scarcity of above-ground vegetation; as nutrias search for food, they dig up root networks and rhizomes for food.<ref name="carter">{{Cite journal|title = Modeling the effects of nutria (''Myocastor coypus'') on wetland loss|date = March 1999|last1 = Carter|first1 = Jacoby|first2 = A. Lee|last2 = Foote|first3 = A.|last3 = Johnson-Randall|display-authors = 1|journal = Wetlands|issue = 1|volume = 19|pages = 209–219|issn = 1943-6246|doi = 10.1007/BF03161750| bibcode=1999Wetl...19..209C |s2cid = 23151277}}{{Closed access}}</ref> 

While nutrias are the most common herbivores in Louisiana marshes, they are not the only ones. Feral hogs, also known as  [[wild boar]]s (''Sus scrofa''), [[swamp rabbit]]s (''Sylvilagus aquaticus''), and [[muskrat]]s (''Ondatra zibethicus'') are less common, but feral hogs are increasing in number in Louisiana wetlands. On plots open to nutria herbivory, 40% less vegetation was found than in plots guarded against nutrias by fences. This number may seem insignificant, and indeed herbivory alone is not a serious cause of land loss, but when herbivory was combined with an additional disturbance, such as fire, single vegetation removal, or double vegetation removal to simulate a tropical storm, the effect of the disturbances on the vegetation were greatly amplified.<ref name="mcfalls"/> 

As different factors were added together, they resulted in less overall vegetation. Adding fertilizer to open plots did not promote plant growth; instead, nutrias fed more in the fertilized areas. Increasing fertilizer inputs in marshes only increases nutria biomass instead of the intended vegetation, therefore increasing nutrient input is not recommended.<ref name="mcfalls"/>  The problem became so serious that Sheriff [[Harry Lee (sheriff)|Harry Lee]] of [[Jefferson Parish]] used [[SWAT]] sharpshooters against the animals.<ref name="ross20071001">{{Cite news |url=http://blog.nola.com/times-picayune/2007/10/jefferson_parish_sheriff_harry_1.html |title=Jefferson Parish Sheriff Harry Lee dies |last=Ross |first=Bob |date=1 October 2007 |work=[[New Orleans Times-Picayune]] |access-date=12 February 2018 |language=en-US |archive-url=https://web.archive.org/web/20071011093504/http://blog.nola.com/times-picayune/2007/10/jefferson_parish_sheriff_harry_1.html |archive-date=11 October 2007 }}</ref>

[[Wetlands]] in general are a valuable resource both economically and environmentally. For instance, the [[U.S. Fish and Wildlife Service]] determined wetlands covered only 5% of the land surface of the contiguous 48 United States, but they support 31% of the nation's plant species.<ref name="functions">{{cite web |title=How do Wetlands Function and Why are they Valuable? |date=2017 |website=EPA |url=https://www.epa.gov/wetlands/how-do-wetlands-function-and-why-are-they-valuable |access-date=19 October 2011 |archive-date=17 July 2018 |archive-url=https://web.archive.org/web/20180717215026/https://www.epa.gov/wetlands/how-do-wetlands-function-and-why-are-they-valuable |url-status=live }}</ref> These very biodiverse systems provide resources, shelter, nesting sites, and resting sites (particularly Louisiana's coastal wetlands such as [[Grand Isle, Louisiana|Grand Isle]] for migratory birds) to a wide array of wildlife. Human users also receive many benefits from wetlands, such as cleaner water, storm surge protection, oil and gas resources (especially on the Gulf Coast), reduced flooding, and chemical and biological waste reduction, to name a few.<ref name="functions"/> In Louisiana, rapid wetland loss occurs due to a variety of reasons; this state loses an estimated area about the size of a football field every hour.<ref name="football">{{cite news |author1=Schleifstein, Mark |title=Louisiana is losing a football field of wetlands an hour, new U.S. Geological Survey study says |work=[[The Times-Picayune]] |date=2 June 2011 |url=http://www.nola.com/environment/index.ssf/2011/06/louisiana_is_losing_a_football.html |access-date=29 November 2011 |archive-date=4 September 2011 |archive-url=https://web.archive.org/web/20110904042051/http://www.nola.com/environment/index.ssf/2011/06/louisiana_is_losing_a_football.html |url-status=live }}</ref>

In 1998, the Louisiana Department of Wildlife and Fisheries (LDWF) conducted the first Louisiana coast-wide survey, which was funded by the [[Coastal Wetlands Planning, Protection, and Restoration Act]] and titled the Nutria Harvest and Wetland Demonstration Program, to evaluate the condition of the marshlands.<ref name="monitoring">{{cite web |date=6 May 1998 |title=Monitoring Plan: Project No. LA-02 Nutria Harvest and Wetland Restoration Demonstration Project |url=http://lacoast.gov/reports/mp/La02.pdf |access-date=16 October 2011 |archive-date=20 October 2011 |archive-url=https://web.archive.org/web/20111020082344/http://lacoast.gov/reports/mp/La02.pdf |url-status=live }}</ref> The survey revealed through aerial surveys of transects that herbivory damage to wetlands totaled roughly {{convert|90,000|acre|ha|order=flip}}. The next year, LDWF performed the same survey and found the area damaged by herbivory increased to about {{convert|105,000|acre|ha|order=flip}}.<ref name="cncp">{{cite web|author1=Jordan, Jillian|author2=Mouton, E.|title=Coastwide Nutria Control Program 2010-2011|url=http://www.nutria.com/uploads/1011CNCPfinalreport.pdf|website=Nutria.com|publisher=Louisiana Department of Wildlife and Fisheries|access-date=18 October 2011|archive-date=25 April 2012|archive-url=https://web.archive.org/web/20120425080621/http://www.nutria.com/uploads/1011CNCPfinalreport.pdf|url-status=live}}</ref> The LDWF has determined the wetlands affected by the nutria decreased from an estimated minimum of {{convert|80,000|acre|ha|order=flip}} of Louisiana wetlands in 2002–2003 season to about {{convert|6,296|acre|ha|order=flip}} during the 2010–2011 season.<ref name="program">{{cite web|title=Program Updates|date=2007|website=Nutria.com|publisher=Louisiana Department of Wildlife and Fisheries|url=http://www.nutria.com/site13.php|access-date=18 October 2011|archive-date=30 August 2011|archive-url=https://web.archive.org/web/20110830121531/http://www.nutria.com/site13.php|url-status=live}}</ref> The LDWF stresses that coastal wetland restoration projects will be greatly hindered without effective, sustainable nutria population control.

=== Pathogenic and viral reservoirs of zoonotic diseases ===
In addition to direct environmental damage, nutrias are the host for a roundworm [[nematode]] [[parasite]] ({{ill|Strongyloides myopotami|qid=Q50410156|s=1|v=sup|italic=y}}) that can infect the skin of humans, causing dermatitis similar to [[strongyloidiasis]].<ref>{{cite web|date=2 February 2019|first=Pranatharthi Haran|last=Chandrasekar |title=Strongyloidiasis: Background, Pathophysiology, Etiology |url=https://emedicine.medscape.com/article/229312-overview|website=Medscape|via=eMedicine|access-date=22 March 2019 |archive-date=9 March 2011 |archive-url=https://web.archive.org/web/20110309020828/http://emedicine.medscape.com/article/999614-overview |url-status=live }}</ref> The condition is also called "nutria itch".<ref name="Itch">{{cite journal |author1=Bonilla, Hector F.|author2=Blanchard, Diane H.|author3=Sanders, Richard |date=June 2000 |title=Nutria Itch |url=https://jamanetwork.com/journals/jamadermatology/article-abstract/190274 |journal=Archives of Dermatology |publisher=JAMA Dermatology |volume=136 |issue=6 |pages=804–805 |doi=10.1001/archderm.136.6.804-a |doi-broken-date=1 July 2025 |pmid=10871960 |access-date=2019-10-06 |archive-date=2019-10-06 |archive-url=https://web.archive.org/web/20191006092152/https://jamanetwork.com/journals/jamadermatology/article-abstract/190274 |url-status=live |url-access=subscription }}</ref> Other parasites they can host are [[tapeworms]], [[liver fluke]]s, and [[blood flukes]]. Waterbody contamination by the nutria occurs through urine and feces.<ref>{{Cite web |last=Animal and Plant Health Inspection Service |first=U.S. Department of Agriculture |date=April 1, 2022 |title=Nutria conflicts with people |url=https://www.aphis.usda.gov/operational-wildlife-activities/nutria |access-date=May 8, 2022 |archive-date=May 22, 2022 |archive-url=https://web.archive.org/web/20220522003504/https://www.aphis.usda.gov/aphis/ourfocus/wildlifedamage/operational-activities/SA_Nutria/CT_Conflicts |url-status=live }}</ref> Nutrias also host [[flea]]s, [[tick]]s and [[chewing louse]].<ref>{{Cite web |last=Greenwood |first=Renetta |date=April 1, 2022 |title=Pacific Northwest Aquatic Invasive Species Profile, Nutria, Myocaster coypus |url=https://depts.washington.edu/oldenlab/wordpress/wp-content/uploads/2013/03/Myocaster-coypus_Greenwood.pdf |access-date=May 8, 2022 |archive-date=May 19, 2022 |archive-url=https://web.archive.org/web/20220519211629/http://depts.washington.edu/oldenlab/wordpress/wp-content/uploads/2013/03/Myocaster-coypus_Greenwood.pdf |url-status=live }}</ref> They can carry several [[zoonotic diseases]] (diseases transmitted from animals to humans). They are reservoirs for [[salmonellosis]], [[encephalomyocarditis virus]], [[chlamydia psittaci]]<ref name="Howerth-1994">{{Cite journal |last1=Howerth |first1=E. W. |last2=Reeves |first2=A. J. |last3=McElveen |first3=M. R. |last4=Austin |first4=F. W. |date=July 1994 |title=Survey for Selected Diseases in Nutria (Myocastor coypus) from Louisiana |journal=Journal of Wildlife Diseases |language=en |volume=30 |issue=3 |pages=450–453 |doi=10.7589/0090-3558-30.3.450 |pmid=7933295 |s2cid=43118277 |issn=0090-3558|doi-access=free }}</ref> and [[antibiotic resistant bacteria]], [[Aeromonas]] spp.<ref name="Lim-2019">{{Cite journal |last1=Lim |first1=Se Ra |last2=Lee |first2=Do-Hun |last3=Park |first3=Seon Young |last4=Lee |first4=Seungki |last5=Kim |first5=Hyo Yeon |last6=Lee |first6=Moo-Seung |last7=Lee |first7=Jung Ro |last8=Han |first8=Jee Eun |last9=Kim |first9=Hye Kwon |last10=Kim |first10=Ji Hyung |date=2019-07-30 |title=Wild Nutria (Myocastor coypus) Is a Potential Reservoir of Carbapenem-Resistant and Zoonotic Aeromonas spp. in Korea |journal=Microorganisms |volume=7 |issue=8 |page=224 |doi=10.3390/microorganisms7080224 |pmid=31366125 |pmc=6723217 |issn=2076-2607|doi-access=free }}</ref>  Other zoonotic disease of concern they are host reservoirs for are [[mycobacterium tuberculosis]], septicemia, [[toxoplasmosis]], and [[rickettsiosis]].<ref>{{Cite journal |last1=Lavelle |first1=Michael J. |last2=Kay |first2=Shannon L. |last3=Pepin |first3=Kim M. |last4=Grear |first4=Daniel A. |last5=Campa |first5=Henry |last6=VerCauteren |first6=Kurt C. |date=December 2016 |title=Evaluating wildlife-cattle contact rates to improve the understanding of dynamics of bovine tuberculosis transmission in Michigan, USA |journal=Preventive Veterinary Medicine |volume=135 |pages=28–36 |doi=10.1016/j.prevetmed.2016.10.009 |pmid=27931926 |issn=0167-5877|doi-access=free }}</ref>  According to the [[Centers for Disease Control and Prevention|CDC]], nutrias carry two out of eight diseases of concern for the United States, [[rabies]] and [[salmonellosis]].<ref>{{Cite web|author=Centers for Disease Control and Prevention |date=May 6, 2019 |title=8 Zoonotic Diseases Shared Between Animals and People of Most Concern in the U.S. |url=https://archive.cdc.gov/#/details?url=https://www.cdc.gov/media/releases/2019/s0506-zoonotic-diseases-shared.html |access-date=June 30, 2024 |archive-date=September 28, 2023 |archive-url=https://web.archive.org/web/20230928231440/https://www.cdc.gov/media/releases/2019/s0506-zoonotic-diseases-shared.html |url-status=live }}</ref> Nutrias are considered a global [[alien species]] and have potential to spread disease to livestock and humans. Nutrias are found on every continent except Australia and Antarctica. Native to the southern hemisphere and spreading globally requires preventive monitoring for zoonotic disease transmission.  Nutria immigration is monitored for [[habitat destruction]] of wetlands, farmlands, marshes and is measured in habitat loss in acres.<ref>{{Cite web |last=Nutria control Program |first=Louisiana Department of Wildlife and Fisheries |date=April 1, 2022 |title=Herbivory Damage and Harvest Maps |url=https://nutria.com/nutria-control-program/herbivory-damage-and-harvest-maps/ |access-date=May 8, 2022 |archive-date=September 28, 2023 |archive-url=https://web.archive.org/web/20230928231443/https://nutria.com/nutria-control-program/herbivory-damage-and-harvest-maps/ |url-status=live }}</ref>  Increased local awareness of viral, bacterial and parasitic transmission from nutria to humans and livestock will be of greater importance as [[climate change]] progresses.

==Control efforts==
As a global alien species, nutrias are monitored and managed throughout the world.  Many countries have attempted eradication efforts with varying degrees of success.
[[File:Nutria_burrow.jpg|thumb|Nutria burrow on bank]]
Nutrias are predicted to expand their range northward over the next century as global temperatures increase.<ref>{{Cite web |last=Israel |first=Brett |date=August 12, 2013 |title=swamp rats on the move as winters warm |url=https://www.scientificamerican.com/article/swamp-rats-on-the-move-as-winters-warm/ |website=Scientific American |access-date=May 8, 2022 |archive-date=May 7, 2022 |archive-url=https://web.archive.org/web/20220507220706/https://www.scientificamerican.com/article/swamp-rats-on-the-move-as-winters-warm/ |url-status=live }}</ref>

=== European Union ===
This species is included since 2016 in the EU list of Invasive Alien Species of Union concern (the Union list).<ref>{{Cite web |title=List of Invasive Alien Species of Union concern |url=https://ec.europa.eu/environment/nature/invasivealien/list/index_en.htm |access-date=2021-07-27 |website=Environment |publisher=European Commission |location=Brussels |archive-date=2017-07-29 |archive-url=https://web.archive.org/web/20170729150050/http://ec.europa.eu/environment/nature/invasivealien/list/index_en.htm |url-status=live }}</ref> This implies that this species cannot be imported, bred, transported, commercialized, or intentionally released into the environment in the whole of the [[European Union]].<ref>{{Cite web |title=Regulation No. 1143/2014 of the European parliament and of the council of 22 October 2014 on the prevention and management of the introduction and spread of invasive alien species |url=https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32014R1143&from=EN |publisher=European Union |date=2014-11-04 |location=Strasbourg |access-date=2021-07-27 |archive-date=2017-03-03 |archive-url=https://web.archive.org/web/20170303185733/http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32014R1143&from=EN |url-status=live }}</ref>

==== Ireland ====
A nutria was first sighted in the wild in [[Republic of Ireland|Ireland]] in 2010. Some nutrias escaped from a pet farm in [[Cork City]] in 2015 and began breeding on the outskirts of the city. Ten were trapped on the [[Curraheen River]] in 2017, but the rodents continued to spread, reaching [[Dublin]] via the [[Royal Canal (Ireland)|Royal Canal]] in 2019.<ref>{{cite news|url=https://www.irishtimes.com/news/environment/invasive-rodent-spotted-along-dublin-s-royal-canal-1.3834367|title=Invasive rodent spotted along Dublin's Royal Canal|first=Olivia|last=Kelly|newspaper=The Irish Times|date=22 March 2019|access-date=22 March 2019|archive-date=28 September 2020|archive-url=https://web.archive.org/web/20200928162240/https://www.irishtimes.com/news/environment/invasive-rodent-spotted-along-dublin-s-royal-canal-1.3834367|url-status=live}}</ref><ref>{{cite magazine |url=https://afloat.ie/inland/inland-waterways/item/42036-appeal-for-sightings-of-invasive-coypu-on-royal-canal-in-dublin |title=Appeal For Sightings Of Invasive Coypu On Royal Canal In Dublin |first=MacDara |last=Conroy |magazine=AFloat (magazine) |date=21 March 2019 |publisher=Baily Publications Ltd |location=Dublin |access-date=22 March 2019 |archive-date=22 March 2019 |archive-url=https://web.archive.org/web/20190322153414/https://afloat.ie/inland/inland-waterways/item/42036-appeal-for-sightings-of-invasive-coypu-on-royal-canal-in-dublin |url-status=live }}</ref><ref>{{cite news |url=https://www.thejournal.ie/large-invasive-rodent-species-that-can-cause-a-lot-of-damage-spotted-along-royal-canal-4555292-Mar2019/ |title=Large invasive rodent species that can 'cause a lot of damage' spotted along Royal Canal |first=Daragh |last=Brophy |newspaper=The Journal (Ireland) |publisher=Journal Media Ltd |location=Dublin |date=22 March 2019 |access-date=22 March 2019 |archive-date=22 March 2019 |archive-url=https://web.archive.org/web/20190322153412/https://www.thejournal.ie/large-invasive-rodent-species-that-can-cause-a-lot-of-damage-spotted-along-royal-canal-4555292-Mar2019/ |url-status=live }}</ref> Animals were found along the [[River Mulkear]] in 2015. The National Biodiversity Data Centre issued a species alert in 2017, saying that nutrias "[have] the potential to be a high impact invasive species in Ireland. […] This species is listed as among 100 of the worst invasive species in Europe."<ref>{{cite web |url=http://www.biodiversityireland.ie/coypu-species-alert/ |title=Coypu Species Alert |date=17 May 2017 |website=National Biodiversity Data Centre |location=Waterford, Ireland |access-date=22 March 2019 |archive-date=22 March 2019 |archive-url=https://web.archive.org/web/20190322153416/http://www.biodiversityireland.ie/coypu-species-alert/ |url-status=live }}</ref>

==== Italy ====
First imported into [[Italy]] in 1928 for fur farming, many animals escaped or were freed deliberately after fur fell out of fashion. The species is mainly found in [[central Italy]] and the [[Po Valley]]. Their presence is more limited in [[southern Italy]] and the [[Insular Italy|islands]], except southern [[Sardinia]], where they are quite widespread. The mayor of the town of [[Gerre de' Caprioli|Gerre de' Caprioli]], Michele Marchi, proposed that the population could be reduced by eating the animals.<ref>{{Cite web |title=Nutria |url=https://torbieresebino.it/en/nature-reserve/nutria/ |url-status=live |archive-url=https://web.archive.org/web/20250425093305/https://torbieresebino.it/en/nature-reserve/nutria/ |archive-date=2025-04-25 |access-date=2025-07-13 |website=Torbiere del Sebino Nature Reserve}}</ref><ref>{{Cite news |last=Squires |first=Nick |date=2018-05-03 |title=As giant rodents thrive in Italy, mayor comes up with novel solution - eat them |url=https://www.telegraph.co.uk/news/2018/05/03/giant-rodents-thrive-italy-mayor-comes-novel-solution-eat/ |url-access=subscription |url-status=live |archive-url=https://web.archive.org/web/20180503124047/https://www.telegraph.co.uk/news/2018/05/03/giant-rodents-thrive-italy-mayor-comes-novel-solution-eat/ |archive-date=2018-05-03 |access-date=2025-07-13 |work=[[Telegraph.co.uk]] |quote=Michele Marchi, the mayor of the town of Gerre de' Caprioli, has suggested that numbers could be reduced if only Italians can develop a taste for coypu meat.}}</ref><ref>{{Cite journal |last1=Panzacchi |first1=Manuela |last2=Cocchi |first2=Roberto |last3=Genovesi |first3=Piero |last4=Bertolino |first4=Sandro |date=1 June 2007 |title=Population control of coypu Myocastor coypus in Italy compared to eradication in UK: a cost-benefit analysis |journal=Wildlife Biology |language=en |publisher=Nordic Society Oikos |volume=13 |issue=2 |pages=159–171 |doi=10.2981/0909-6396(2007)13[159:PCOCMC]2.0.CO;2 |issn=0909-6396 |eissn=1903-220X |doi-access=free}}</ref>

=== Great Britain===
In the UK, nutrias escaped from fur farms and were reported in the wild as early as 1932. There were three unsuccessful attempts to control the nutria in [[East Anglia]] between 1943 and 1944. Nutria population and range increased, causing damage to agriculture in the 1950s. During the 1960s, a grant was awarded to rabbit clearance societies that included nutria.<ref>{{cite book |title=Agriculture in Britain |date=1961 |publisher=B.I.S. |page=22 |url=https://books.google.com/books?id=W0KdZjrzbl0C&pg=PA22 |language=en |access-date=2023-03-21 |archive-date=2023-04-21 |archive-url=https://web.archive.org/web/20230421152550/https://books.google.com/books?id=W0KdZjrzbl0C&pg=PA22 |url-status=live }}</ref> This control allowed for the removal of 97,000 nutria in 1961 and 1962. From 1962 to 1965, 12 trappers were hired to eradicate as many nutrias as possible confining the remaining population within the [[Norfolk Broads]]. The campaign used live traps allowing non-target species to be released while any nutrias caught were shot. Combined with cold winters in 1962 to 1963, almost 40,500 nutrias were removed from the population. Although nutria populations were greatly reduced after the 1962–1965 campaign ended, the population increased until another eradication campaign began in 1981. This campaign succeeded in fully eradicating the nutria in Great Britain. The trapping areas were broken into eight sectors leaving no area uncontrolled. The 24 trappers were offered an incentive for early completion of the 10-year campaign. In 1989 nutrias were assumed eradicated, as only three males were found between 1987 and 1989.<ref name="Baker2010">{{cite journal|last1=Baker|first1=S.|date=2010|title=control and eradication of invasive mammals in Great Britain|journal=Revue Scientifique et Technique (International Office of Epizootics)|volume=29|issue=2|pages=311–327|doi=10.20506/rst.29.2.1981|pmid=20919585|doi-access=free}}</ref>

=== Japan ===
[[File:Nutria Osaka Japan - 12-05-2024.jpg|thumb|A nutria on the banks of a river in Osaka, Japan.]]
Nutrias were introduced to Japan in 1939. They were imported from France during [[World War II]] to address food shortages as well as the fur trade. After the war in 1950, many nutrias were released en masse or escaped, and became one of Japan's worst invasive species, damaging river banks, rice fields and other valuable crops.<ref>{{Cite web |publisher=National Institute for Environmental Studies; National Research and Development Agency |date=April 1, 2022 |title=Invasive species of Japan |url=https://www.nies.go.jp/biodiversity/invasive/DB/detail/10140e.html |location=Ibaraki, Japan |access-date=May 8, 2022 |archive-date=July 1, 2022 |archive-url=https://web.archive.org/web/20220701070113/https://www.nies.go.jp/biodiversity/invasive/DB/detail/10140e.html |url-status=live }}</ref> In 1963 an eradication program was started to remove nutrias but has shown little to no success. Nutrias are still present in Japan and there is a restriction on importing, transporting and obtaining nutrias per the Invasive Alien Species Act established in 2004.<ref>{{Cite web |date=2004-06-02 |title=Invasive Alien Species Act |url=https://www.env.go.jp/en/nature/as/040427.pdf |publisher=Government of Japan |location=Tokyo |id=Law No. 78 (June 2, 2004) |access-date=2022-05-08 |archive-date=2022-04-24 |archive-url=https://web.archive.org/web/20220424004319/http://www.env.go.jp/en/nature/as/040427.pdf |url-status=live }}</ref>

===New Zealand===
Nutrias are classed as a "prohibited new organism" under New Zealand's [[Hazardous Substances and New Organisms Act 1996]], preventing it from being imported into the country.<ref>{{cite web|url=http://legislation.govt.nz/act/public/1996/0030/latest/DLM386556.html#DLM386556|title=Hazardous Substances and New Organisms Act 2003 - Schedule 2 Prohibited new organisms|publisher=New Zealand Government|access-date=26 January 2012|archive-date=16 June 2012|archive-url=https://web.archive.org/web/20120616104517/http://legislation.govt.nz/act/public/1996/0030/latest/DLM386556.html#DLM386556|url-status=live}}</ref>

===United States===
[[File:A trap for capturing nutria.jpg|thumb|Trap for capturing nutria]]

====Atlantic Coast====
An eradication program on the [[Delmarva Peninsula]], between [[Chesapeake Bay]] and the [[East Coast of the United States|Atlantic Coast]], where nutrias once numbered in the tens of thousands and had destroyed thousands of hectares of marshland, had nearly succeeded by 2012.<ref name=NYT070512>{{cite news|title=Killed by Thousands, Varmint Will Never Quit|url=https://www.nytimes.com/2012/07/06/us/new-war-on-invasive-nutria-in-delmarva-marshlands.html|access-date=July 6, 2012|newspaper=The New York Times|date=July 5, 2012|author=Emery, Theo|archive-date=July 5, 2012|archive-url=https://web.archive.org/web/20120705203818/http://www.nytimes.com//2012/07/06/us/new-war-on-invasive-nutria-in-delmarva-marshlands.html|url-status=live}}</ref> In September 2022, government officials announced that nutrias had been completely eradicated on the [[Maryland Eastern Shore]].<ref>{{cite web |title=Decades-long Partnership Eradicates Destructive Nutria Rodents from Maryland |url=https://www.fws.gov/press-release/2022-09/decades-long-partnership-eradicates-destructive-nutria-rodents-maryland |date=2022-09-16 |publisher=U.S. Fish and Wildlife Service |location=Hadley, MA |id=Press Release |access-date=2022-09-16 |archive-date=2022-09-16 |archive-url=https://web.archive.org/web/20220916193322/https://www.fws.gov/press-release/2022-09/decades-long-partnership-eradicates-destructive-nutria-rodents-maryland |url-status=live }}</ref><ref>{{cite web |last=Fenston |first=Jacob |title=Maryland Has Eradicated These Invasive 20-Lb. Swimming Rodents |url=https://dcist.com/story/22/09/16/maryland-eradicated-invasive-nutria-rodents/ |date=2022-09-16 |website=DCist |publisher=WAMU 88.5 Radio |location=Washington, D.C. |access-date=2022-09-16 |archive-date=2022-09-16 |archive-url=https://web.archive.org/web/20220916190753/https://dcist.com/story/22/09/16/maryland-eradicated-invasive-nutria-rodents/ |url-status=live }}</ref>

====California====
The first records of nutrias invading California dates from the 1940s and 1950s, when the species was found in the agriculture-rich [[Central Valley of California|Central Valley]] and the south coast of the state, but by the 1970s the animals had been [[wikt:extirpate|extirpated]] statewide.<ref name="CDFW2019">{{cite web |title=California's Invaders: Nutria |url=https://www.wildlife.ca.gov/Conservation/Invasives/Species/Nutria |website=Habitat Conservation Planning Branch |publisher=[[California Department of Fish and Wildlife]] |access-date=21 July 2019 |archive-date=21 July 2019 |archive-url=https://web.archive.org/web/20190721032211/https://www.wildlife.ca.gov/Conservation/Invasives/Species/Nutria |url-status=live }}</ref> They were found again in [[Merced County]] in 2017, on the edge of the [[Sacramento–San Joaquin River Delta|San Joaquin River Delta]]. State officials are concerned that they will harm infrastructure that sends water to [[San Joaquin Valley]] farms and urban areas.<ref>{{Cite web|url=https://www.latimes.com/local/lanow/la-me-ln-nutria-invasion-20190212-story.html|title=You think the rats at L.A. City Hall are bad? Officials have a $1.9-million plan to rid state marshlands of giant rodents|last=Fry|first=Hannah|date=February 16, 2019|website=[[Los Angeles Times]]|access-date=16 February 2019|archive-date=16 February 2019|archive-url=https://web.archive.org/web/20190216181236/https://www.latimes.com/local/lanow/la-me-ln-nutria-invasion-20190212-story.html|url-status=live}}</ref> In 2019, the [[California Department of Fish and Wildlife]] (CDFW) received nearly $2 million in [[Governor of California|Governor]] [[Gavin Newsom]]'s first budget, and an additional $8.5 million via the Delta Conservancy (a state agency focused on the Delta) to be spent over the course of three years.<ref name="Ferguson2019">{{cite news |last1=Ferguson |first1=Cat |title=California pledges millions to battle enormous, destructive swamp rats |url=https://www.mercurynews.com/2019/07/16/california-pledges-millions-to-battle-enormous-destructive-swamp-rats/ |access-date=21 July 2019 |work=[[San Jose Mercury News]] |date=July 16, 2019 |archive-date=17 July 2019 |archive-url=https://web.archive.org/web/20190717215422/https://www.mercurynews.com/2019/07/16/california-pledges-millions-to-battle-enormous-destructive-swamp-rats/ |url-status=live }}</ref> The state has adopted an eradication campaign based on the successful effort in the [[Chesapeake Bay]], including strategies such as the "[[Judas animal|Judas]] nutria" (in which individualized nutrias are caught, sterilized, fitted with [[radio collar]]s, and  released, whereupon they can be tracked by hunters as they return to their colonies) and the use of trained dogs.<ref name="Ferguson2019"/> The state has also reversed a prior "no-hunting" policy, although hunting the animals does require a license.<ref name="Ferguson2019"/> California has a restriction on importation and transportation without a permit.<ref name="Ca.Gov"/> If nutrias are found or captured in the state of California, local authorities must be notified right away and the nutrias cannot be released. Licensed hunters in the state of California may hunt nutrias as a non-game animal. Bounty programs are not advised in California due to native species of muskrat and beaver being misidentified.<ref>{{Cite web |date=June 6, 2019 |title=Why no bounty program for nutria? |url=https://californiaoutdoors.wordpress.com/2019/06/06/why-no-bounty-program-for-nutria/ |website=California Outdoors |access-date=May 8, 2022 |archive-date=March 6, 2021 |archive-url=https://web.archive.org/web/20210306105527/https://californiaoutdoors.wordpress.com/2019/06/06/why-no-bounty-program-for-nutria/ }}</ref>

====Louisiana====
The Louisiana Coastwide Nutria Control Program provides incentives for harvesting nutria. Starting in 2002, the Louisiana Department of Wildlife and Fisheries (LDWF) performed aerial surveys just as they had done for the Nutria Harvest and Wetland Demonstration Program, except under a different program title. Under the Coastwide Nutria Control Program, which also receives funds from [[CWPPRA]], 308,160 nutrias were harvested the first year (2002–2003), revealing {{convert|82,080|acre|ha|order=flip}} damage and totaling $1,232,640 in incentive payouts to those legally participating in the program.<ref name="program"/> Essentially, once a person receives a license to hunt or trap nutria, that person is allowed to capture an unlimited number. When a nutria is captured, the tail is cut off and turned in to a Coastal Environments Inc. (CEI) official at an approved site. As of 2019, each nutria tail is worth $6, which is an increase from $4 before the 2006–2007 season.<ref>{{cite web |title=Louisiana Coastwide Nutria Control Program |url=https://www.nutria.com/site10.php |access-date=January 15, 2021 |publisher=Louisiana Department of Wildlife and Fisheries |location=Lafayette, LA |archive-date=February 25, 2021 |archive-url=https://web.archive.org/web/20210225041151/https://nutria.com/site10.php |url-status=live }}</ref> Nutria harvesting increased drastically during the 2009–2010 season, with 445,963 nutria tails turned in worth $2,229,815 in incentive payments.<ref name="program"/> Each CEI official keeps record of how many tails have been turned in by each individual per parish, the method used in capture of the nutria, and the location of capture. All of this information is transferred to a database to calculate the density of nutrias across the Louisiana coast, and the LDWF combines these data with the results from the aerial surveys to determine the number of nutrias remaining in the marshes and the amount of damage they are inflicting on the ecosystem.<ref name="program"/>

Another program executed by LDWF involves creating a market of nutria meat for human consumption, though it is still trying to gain public notice. Nutria is a very lean, protein-rich meat, low in fat and cholesterol with the taste, texture, and appearance of rabbit or dark turkey meat.<ref name="Fur_Breeder">{{cite book |title=American Fur Breeder |date=1964 |page=96 |edition=37 |quote=Rabbit and nutria meat are also fed on ranches. Both are lean and good sources of quality protein. Nutria, in particular, has been increasingly available in recent years. It is low in fat and leaner than either horse or rabbit meat}}</ref>  Few [[pathogens]] are associated with the meat, but proper heating when cooking should kill them. The quality of the meat and the minimal harmful microorganisms associated with it make nutria meat an "excellent food product for export markets".<ref name="meat"/>

Several desirable control methods are ineffective for various reasons. [[Zinc phosphide]] is the only rodenticide registered to control nutria, but it is expensive, remains toxic for months, detoxifies in high humidity and rain, and requires construction of expensive floating rafts for placement of the chemical. It is not yet sure how many nontarget species are susceptible to zinc phosphide, but birds and rabbits have been known to die from ingestion.<ref name="brochure">{{cite web |title=Nutria in Louisiana |date=2002 |url=http://www.nutria.com/uploads/0232.brochurerev.pdf |publisher=Louisiana Department of Wildlife & Fisheries |location=New Iberia, LA |access-date=3 November 2011 |archive-date=15 September 2011 |archive-url=https://web.archive.org/web/20110915213326/http://www.nutria.com/uploads/0232.brochurerev.pdf |url-status=live }}</ref> Therefore, this chemical is rarely used, especially not in large-scale projects. Other potential chemical pesticides would be required by the US Environmental Protection Agency to undergo vigorous testing before being acceptable to use on nutria. The LDWF has estimated costs for new chemicals to be $300,000 for laboratory, chemistry, and field studies, and $500,000 for a mandatory Environmental Impact Statement.<ref name="brochure"/> Contraception is not a common form of control, but is preferred by some wildlife managers. It is also expensive to operate– an estimated $6 million annually to drop bait laced with birth-control chemicals. Testing of other potential contraceptives would take about five to eight years and $10 million, with no guarantee of FDA approval.<ref name="brochure"/> Also, an intensive environmental assessment would have to be completed to determine whether any non-target organisms were affected by the contraceptive chemicals. Neither of these control methods is likely to be used in the near future.{{Citation needed|date=January 2012}}

In Louisiana, a claimed environmentally sound solution is the killing of nutrias to make dog food treats.<ref name="Dodge"/>

==Gallery==
<gallery class="center">
Nutria heart. (Myocastor coypus).jpg|Nutria heart
Nutriaschädel.jpg|Skull from various perspectives
Nutria (Myocastor coypus) in a partially frozen river Ljubljanica.jpg|By the river [[Ljubljanica]]
Coypus.jpg|Feral nutria in Oise river in France
File:Myocastor coypus 2016 G2.jpg|10-day-old baby nutria
File:Tropy nutrii.jpg|[[Animal track|Track]]
</gallery>

==References==
{{Reflist}}

==Further reading==
{{Refbegin}}
* Sandro Bertolino, Aurelio Perrone, and Laura Gola "Effectiveness of coypu control in small Italian wetland areas" ''Wildlife Society Bulletin'' Vol. 33, No. 2 (June 2005) pp.&nbsp;714–772.
* Carter, Jacoby and Billy P. Leonard: "A Review of the Literature on the Worldwide Distribution, Spread of, and Efforts to Eradicate the Coypu (Myocastor coypus)" ''Wildlife Society Bulletin'', Vol. 30, No. 1 (Spring, 2002), pp.&nbsp;162–175.
* Carter, J., A.L. Foote, and L.A. Johnson-Randall. 1999. "Modeling the effects of nutria (Myocastor coypus) on wetland loss". ''Wetlands'' 19(1):209–219
* Lauren E. Nolfo-Clements: ''Seasonal variations in habitat availability, habitat selection, and movement patterns of Myocastor coypus on a subtropical freshwater floating marsh.'' (Dissertation) [[Tulane University]]. New Orleans. 2006. {{ISBN|0-542-60916-9}}
* Sheffels, Trevor and Mark Systma. "Report on Nutria Management and Research in the Pacific Northwest" Center for Lakes and Reservoir Environmental Sciences and Resources, Portland State University. December 2007.  Available on-line: [https://web.archive.org/web/20100605003204/http://www.clr.pdx.edu/docs/CLR_nutria_report.pdf]
{{Refend}}

== External links ==
{{Commons category|Myocastor coypus}}
{{Wiktionary}}
* The documentary ''[http://www.rodentsofunusualsize.tv/ Rodents of Unusual Size]'' tells the story of the introduction of nutria to Louisiana and the creative efforts being used in the attempts to eradicate them.
* [https://www.aphis.usda.gov/aphis/maps/sa_wildlife_services/ct_nutria_story_map Saving the Bay: The History of the Chesapeake Bay Nutria Eradication Project] {{Webarchive|url=https://web.archive.org/web/20220920170838/https://www.aphis.usda.gov/aphis/maps/sa_wildlife_services/ct_nutria_story_map |date=2022-09-20 }} – USDA/Animal and Plant Health Inspection Service
* [https://web.archive.org/web/20100505021325/http://www.clr.pdx.edu/projects/ans/nutria.php Portland State University] - Report on nutrias in the Pacific Northwest of North America.
* [https://www.invasivespeciesinfo.gov/profile/nutria Species Profile – Nutria (''Myocastor coypus'')], National Invasive Species Information Center, [[United States National Agricultural Library]]. Lists general information and resources for nutria.

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