Myocastor coypus (coypu)
- Summary of Invasiveness
- Taxonomic Tree
- Distribution Table
- Habitat List
- Biology and Ecology
- Means of Movement and Dispersal
- Pathway Causes
- Impact Summary
- Threatened Species
- Risk and Impact Factors
- Uses List
- Similarities to Other Species/Conditions
- Prevention and Control
- Links to Websites
- Principal Source
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Myocastor coypus (Molina, 1782)
Preferred Common Name
International Common Names
- English: nutria
- Spanish: coipù
- French: ragondin
- Portuguese: ratão-do-banhado
Local Common Names
- Germany: Biberratte; Sumpfbiber
Summary of InvasivenessTop of page
Myocastor coypus (coypu) is a large semi-aquatic rodent which originated from South America. However, due to escapes and releases from fur farms there are now large feral populations in North America, Europe and Asia. Their burrows penetrate and damage river banks, dykes and irrigation facilities. M. coypus' feeding methods lead to the destruction of large areas of reed swamp. Habitat loss caused by coypus impacts plant, insect, bird and fish species. This species has been nominated as one of the "100 of the World's Worst" invaders by IUCN. An alert for this species in Ireland was the first Species Alert issued by a European Union Member State under the EU Regulation on Invasive Alien Species (1143/2014).
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Chordata
- Subphylum: Vertebrata
- Class: Mammalia
- Order: Rodentia
- Family: Myocastoridae
- Genus: Myocastor
- Species: Myocastor coypus
DescriptionTop of page
Myocastor coypus (coypu) is a large rodent (5-9kg; 40-60cm body; 30-45cm tail), superficially rat-like, pelage brown and yellow-brown in colour with a cylindrical tail. It has webbed hindfeet, with a footprint up to 15cm long, imprints of the web is often visible; incisors are prominent and bright orange-yellow (unlike rats which are yellow-brown), with white marks on muzzle (Woods et al. 1992, Carter and Leonard 2002). Faeces cylindrical, up to 70mm long, with fine longitudinal striations (LeBlanc, 1994).
DistributionTop of page
Native range: Native to South America south of 23 degree latitude, including Argentina, Bolivia, southern Brazil, Chile, Paraguay, and Uruguay (Carter and Leonard 2002).
Known introduced range: Introduced to areas of North America, Europe, Africa and Asia (Carter, 2007).
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|China||Present only in captivity/cultivation||Introduced||early 1960s||Invasive||ISSG, 2011|
|Georgia (Republic of)||Present||Introduced||1930-1932||Invasive||ISSG, 2011|
|Korea, Republic of||Present||Introduced||Invasive||ISSG, 2011|
|Botswana||Unconfirmed record||Introduced||pre 1958||Invasive||ISSG, 2011|
|Tanzania||Present||Introduced||Not invasive||ISSG, 2011|
|Zambia||Unconfirmed record||Introduced||pre 1958||Invasive||ISSG, 2011|
|Zimbabwe||Unconfirmed record||Introduced||pre 1958||Invasive||ISSG, 2011|
|Canada||Present||Present based on regional distribution.|
|-British Columbia||Present||Introduced||Invasive||ISSG, 2011|
|-Nova Scotia||Present only in captivity/cultivation||Introduced||Invasive||ISSG, 2011|
|Mexico||Unconfirmed record||Introduced||Invasive||ISSG, 2011|
|-Arkansas||Present||Introduced||late 1940s||Invasive||ISSG, 2011|
|-Idaho||Unconfirmed record||Introduced||Invasive||ISSG, 2011|
|-Illinois||Unconfirmed record||Introduced||Invasive||ISSG, 2011|
|-Indiana||Present only in captivity/cultivation||Introduced||Invasive||ISSG, 2011|
|-Kansas||Unconfirmed record||Introduced||Invasive||ISSG, 2011|
|-Kentucky||Absent, formerly present||Introduced||Invasive||ISSG, 2011|
|-Louisiana||Restricted distribution||Introduced||early 1930s||Invasive||ISSG, 2011|
|-Michigan||Present only in captivity/cultivation||Introduced||1930s||Invasive||ISSG, 2011|
|-Minnesota||Present only in captivity/cultivation||Introduced||Invasive||ISSG, 2011|
|-Missouri||Unconfirmed record||Introduced||Invasive||ISSG, 2011|
|-Montana||Unconfirmed record||Introduced||Invasive||ISSG, 2011|
|-Nebraska||Absent, formerly present||Introduced||Invasive||ISSG, 2011|
|-New Mexico||Present||Introduced||Invasive||ISSG, 2011|
|-North Carolina||Present||Introduced||Invasive||ISSG, 2011|
|-Ohio||Present only in captivity/cultivation||Introduced||1937||Invasive||ISSG, 2011|
|-Utah||Present only in captivity/cultivation||Introduced||1939||Invasive||ISSG, 2011|
|-Virginia||Unconfirmed record||Introduced||Invasive||ISSG, 2011|
|-Washington||Present||Introduced||late 1930s||Invasive||ISSG, 2011|
|Argentina||Present||Native||Not invasive||ISSG, 2011|
|Bolivia||Present||Native||Not invasive||ISSG, 2011|
|Brazil||Present||Native||Not invasive||ISSG, 2011|
|Chile||Present||Native||Not invasive||ISSG, 2011|
|Paraguay||Present||Native||Not invasive||ISSG, 2011|
|Uruguay||Present||Native||Not invasive||ISSG, 2011|
|Czech Republic||Present||Introduced||Invasive||ISSG, 2011|
|Denmark||Absent, formerly present||Introduced||Invasive||ISSG, 2011|
|Finland||Absent, formerly present||Introduced||Invasive||ISSG, 2011|
|Ireland||Restricted distribution||Introduced||2010||Invasive||National Biodiversity Data Centre, 2017||Under Eradication. Individual animals removed from River Mulkear in Tipperary and Limerick in 2015; 10 animals removed from Cork City in 2016|
|Netherlands||Restricted distribution||Introduced||around 1930||Invasive||ISSG, 2011|
|Norway||Absent, formerly present||Introduced||Invasive||ISSG, 2011|
|Russian Federation||Present||Introduced||1926||Invasive||ISSG, 2011|
|Sweden||Absent, formerly present||Introduced||Invasive||ISSG, 2011|
|Switzerland||Unconfirmed record||Introduced||Invasive||ISSG, 2011|
|UK||Eradicated||Introduced||late 1920s||Invasive||ISSG, 2011|
HabitatTop of page
Myocastor coypus (coypu) are generally found near permanent water, particularly reed beds and swamp/marsh. Also found in rivers, streams, lakes, ponds and brackish marsh in coastal areas.They prefer habitats near the water, animals are rarely observed over 100m away from river. Severe winter could reduce reproductive success and adult survival.
Habitat ListTop of page
|Terrestrial ‑ Natural / Semi-natural||Riverbanks||Present, no further details|
|Wetlands||Present, no further details|
|Coastal areas||Present, no further details|
|Lakes||Present, no further details|
|Rivers / streams||Present, no further details|
Biology and EcologyTop of page Nutrition
Herbivorous, Myocastor coypus (coypu) eat wetland plants and crops. Selective feeding causes massive reduction in reed swamp. Occasional feeding on freshwater mussels are reported. It practices coprophagy. (Woods et al. 1992, Carter and Leonard 2002, Genesis Laboratories, Inc. 2002).
Placental. Sexual. Significant relationship between winter severity and female reproduction in the following spring. Prenatal embryo losses are high until 13-14 weeks of gestation. Sexual maturity 3-10 months. Gestation 127-138 days. Litter size 2-9; prenatal embryo losses are common during cold winter and in females in poor health condition. (Woods et al. 1992, Genesis Laboratories, Inc. 2002).
Myocastor coypus (coypu) breed throughout the year; post-partum oestrus. Sexual maturity 3-10 months. Gestation 127-138 days. Mean litter sizes 5-6 (2-9), prenatal embryo losses are common during cold winter and in females in poor health condition. Woods et al. 1992).
Means of Movement and DispersalTop of page Introduction pathways to new locations
Other: Fur farms, introduced for fur exploitation.
Local dispersal methods
Escape from confinement:
Natural dispersal (local):
Pathway CausesTop of page
|Escape from confinement or garden escape||Yes|
Impact SummaryTop of page
ImpactTop of page
Myocastor coypus (coypu) burrows undermine the banks of rivers and dykes causing instability (Carter and Leonard, 2002). Feeding on rhizomes and young shoots of marsh plants leads to plant community breakdown and can lead to erosion in coastal habitats (LeBlanc, 1994). Coypu feeding on sea oat rhizomes in Mississippi barrier islands have led to sand dune erosion in these important habitats (GSMFC 2005).
At high densities coypu are able to convert marshland to open water by feeding on plants. Habitat destruction caused by coypu threatens rare marshland species of bird, fish and invertebrates. In Italy coypu have caused breeding whiskered tern (Chlidonias hybrida) to decline by largely destroying the cover of water-lilies Nymphaea in Valli di Argenta a designated IBA (Important Bird Area). The habitats of two national treasure species in Japan - a critically endangered dragon fly (see Libellula angelina in IUCN Red List of Threatened Species) and a fish the vulnerable deep-bodied bitterling (see Acheilognathus longipinnis in IUCN Red List of Threatened Species) (Shirow Tatsuzawa, pers. Comm.) are threatened by coypu.
Coypu also feed on agricultural crops (Carter and Leonard 2002) including sugarcane, alfalfa and root crops (Woods et al. 1992).
Threatened SpeciesTop of page
|Threatened Species||Conservation Status||Where Threatened||Mechanism||References||Notes|
|Acheilognathus longipinnis||VU (IUCN red list: Vulnerable) VU (IUCN red list: Vulnerable)||ISSG, 2011|
|Chlidonias hybridus||LC (IUCN red list: Least concern) LC (IUCN red list: Least concern)||Italy||ISSG, 2011|
|Libellula angelina||CR (IUCN red list: Critically endangered) CR (IUCN red list: Critically endangered)||ISSG, 2011|
|Zizania texana (Texas wild-rice)||USA ESA listing as endangered species USA ESA listing as endangered species||Texas||Herbivory/grazing/browsing||US Fish and Wildlife Service, 1995|
Risk and Impact FactorsTop of page Invasiveness
- Proved invasive outside its native range
- Highly adaptable to different environments
- Tolerant of shade
- Highly mobile locally
- Has high reproductive potential
- Damaged ecosystem services
- Ecosystem change/ habitat alteration
- Modification of hydrology
- Modification of successional patterns
- Negatively impacts agriculture
- Reduced native biodiversity
- Threat to/ loss of endangered species
- Threat to/ loss of native species
UsesTop of page
Myocastor coypus (coypu) are valued as a source of fur (Carter and Leonard 2002) and have been used as a meat source. Coypu provides prey for alligators and other native predators in some areas.
Uses ListTop of page
Similarities to Other Species/ConditionsTop of page
Musk rats (Ondatra zibethicus) are native to north America and occupy same aquatic habitats as coypu. They have been introduced to areas of South America, Europe and Asia so may be found in the same areas as coypu. Musk rats are smaller than coypu and have a laterally flattened tail compared to the coypu's rounded one.
Prevention and ControlTop of page
M. coypus is included in the EU Regulation on Invasive Alien Species (1143/2014) which came into force on 15 January 2015 and requires that European Member States take action to prevent the introduction and spread of listed species. A coypu alert in Ireland was the first species alert issued by a Member State under this regulation. The response was to capture individuals, increase public awareness and provide a mechanism for reporting sightings (National Biodiversity Data Centre, 2017).
Feral populations of coypu are managed by shooting and trapping. Eradication is preferable for small to medium size populations but some level of control is essential in most cases if eradication is not feasible. High fur prices can help encourage sufficient hunting to control populations (Carter and Leonard 2002). In times of high fur prices little damage was observed to wetlands in Louisiana, USA (Marx et al. 2003). In 2002 a bounty system existed in Louisiana. That year a $12.5 million investment resulted in 342 trappers returning 300,000 tails over a 4 month season. Animals were shot or trapped and carcasses were either retained and sold as pelts or disposed of in the wetlands (Marx et al. 2003). Coypu have been eradicated from a number of states in the USA and are classed as pests in countries throughout the world (Carter and Leonard, 2002). A population of around 6000 coypu (Genovesi, 2005) was eradicated from East Anglia, UK in a campaign using cage traps. 24 trappers were employed for 8 years at a cost of £2.5 million (Gosling, 1989). An eradication was proposed for a small lake in Sicily but opposition by the World Wildlife Fund (WWF) prevented the eradication taking place (Genovesi, 2005). An unsuccessful attempt was made to use pythons (Python rebae) as a biocontrol for coypu in Lake Navaisha in Keya (Harper et al. 1990).
BibliographyTop of page
Abbas, A. 1991. Feeding strategy of coypu (Myocastor coypus) in central western France. Journal of Zoology, London, 224: 385-401.
Bomford, M., 2003. Risk Assessment for the Import and Keeping of Exotic Vertebrates in Australia. Bureau of Rural Sciences, Canberra. http://www.feral.org.au/feral_documents/PC12803.pdf
Borgnia, M., Galante, M. L. and Cassini, M. H. 2000. Diet of the coypu (Nutria, Myocastor coypus) in agro-systems of Argentina Pampas. Journal of Wildlife Management 64(2): 354-361.
Carter, J. and Leonard, B. P. 2002. A review of the literature on the worldwide distribution., spread of, and efforts to eradicate the coypu (Myocastor coypus) Source. Wildlife Society Bulletin. 30(1): 162-175.
Carter, Jacoby., 2007. Worldwide Distribution, Spread of, and Efforts to Eradicate the Nutria (Myocastor coypus) USGS National Wetlands Research Center http://www.nwrc.usgs.gov/special/nutria/index.htm
CONABIO. 2008. Sistema de información sobre especies invasoras en México. Especies invasoras - Mamíferos. Comisión Nacional para el Conocimiento y Uso de la Biodiversidad. Fecha de acceso. http://www.conabio.gob.mx/invasoras/index.php/Especies_invasoras_-_Mam%C3%ADferos
Fasham, M; Trumper, Kate., 2001. Review of non-native species legislation and guidance Department for Environment, Food & Rural Affairs http://www.defra.gov.uk/wildlife-pets/wildlife/management/non-native/documents/review-report.pdf
Genesis Laboratories, Inc. 2002. Report prepared for the Lousiana Department of Wildlife and Fisheries. 155pp.
Genovesi, P. 2005. Eradications of invasive alien species in Europe: a review. Biological Invasions. 7 (1): 127-133.
Gosling, L. M. 1989. Extinction to order. New Scientist, 4 march 1989: 44-49.
Gosling, L. M. and Baker, S. J. 1987. Planning and monitoring an attempt to eradicate coypus from Britain. Symposia of The Zoological Society of London 58: 99-113.
Gosling, L. M., Baker, S. J. and Clarke, C. N. 1988. An attempt to remove coypus (Myocastor coypus) from a wetland habitat in East Anglia. Journal of Applied Ecology 25: 49-62.
Gulf States Marine Fisheries Commission (GSMFC), 2005. Myocastor coypus (Kerr, 1792)
Harper, D.M., Mavuti, K.M. and Muchiri, S.M., 1990. Ecology and management of Lake Naivasha, Kenya, in relation to climatic change, alien species' introduction, and agricultural development. Environmental Conservation 17: 328-336.
IUCN/SSC Invasive Species Specialist Group (ISSG)., 2010. A Compilation of Information Sources for Conservation Managers Involved in the Prevention, Eradication, Management and Control of the Spread of Invasive Alien Species that are a Threat to Native biodiversity and Natural Ecosystems.
LeBlanc, Dwight J. 1994. Nutria Prevention and control of wildlife damage. (Eds) Scott E. Hygnstrom Robert M. Timm & Gary E. Larson http://www.ces.ncsu.edu/nreos/wild/pdf/wildlife/NUTRIA.PDF
Marx, J., Mouton, E., Linscombe, G. 2003. Nutria harvest distribution 2002-2003 And A survey of nutria herbivory damage in coastal Louisiana in 2003. Unpublished report by Fur and Refuge Division, Louisiana Department of Wildlife and Fisheries.
Mendelssohn H & Y Yom-Tov, 1987. Eds. Vol 7: Mammals. Plants and Animals of the Land of Israel. Ministry of Defence/The Publishing House, Society for the Protection of Nature in Israel.
Reggiani, G., Boitani, L. and De Stefano, R. 1995. Population dynamics and regulation in the coypu Myocastor coypus in central Italy. Ecography 18: 138-146.
Reggiani, G., Boitani, L., D'Antoni, S. and De Stefano, R. 1993. Biology and control of the coypu in the mediterranean area. Suppl. Ric. Biol. Selvaggina XXI: 67-100.
Tatsuzawa, Shirow. Department of Regional Science, Hokkaido University, Japan.
Willner, G. R., Chapman, J. A. and Pursley, D. 1979. Reproduction, physiological responses, food habits, and abundance of nutria on Maryland marshes. Wildlife Monograph 65: 43.
Woods, C.A., Contreras, L., Willner-Chapman, G. & Whidden, H.P. 1992. Myocastor coypus. Mammalian Species 398: 1-8.
ReferencesTop of page
National Biodiversity Data Centre, 2017. Coypu Species Alert. Kilkenny, Ireland: Heritage Council. http://www.biodiversityireland.ie/coypu-species-alert/
ContributorsTop of page
- Last Modified: Sunday, April 13, 2008
Distribution MapsTop of page
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