The nutria (''Myocastor coypus''), also known as the coypu,
is a large, herbivorous, semiaquatic rodent
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...
.
Classified for a long time as the only member of the family Myocastoridae, ''Myocastor'' is now included within Echimyidae, the family of the spiny rats.[ ]
The nutria lives in burrows alongside stretches of water, and feeds on river plant stems.[ ] Originally native to subtropical and temperate South America, it has since been introduced to North America, Europe, Asia, and Africa, primarily by fur farmers. Although it is still hunted and trapped for 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
An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...
. Nutria also transmit various diseases to humans and animals mainly through water contamination.
Etymology
The genus name ''Myocastor'' derives from the two Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...
words (), meaning "rat, mouse", and (), meaning "beaver". Literally, therefore, the name ''Myocastor'' means "mouse beaver".
Two names are commonly used in English
English usually refers to:
* English language
* English people
English may also refer to:
Peoples, culture, and language
* ''English'', an adjective for something of, from, or related to England
** English national ide ...
for ''Myocastor coypus''. The name "nutria" (from Spanish word ''nutria'', meaning 'otter') is generally used in North America, Asia, and throughout countries of the former Soviet Union; however, in most Spanish-speaking countries, the word "nutria" refers primarily to the otter
Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic, or marine, with diets based on fish and invertebrates. Lutrinae is a branch of the Mustelidae family, which also includes wea ...
. To avoid this ambiguity, the name "coypu" or "coipo" (derived from the Mapudungun language
Mapuche (, Mapuche & Spanish: , or Mapudungun; from ' 'land' and ' 'speak, speech') is an Araucanian language related to Huilliche spoken in south-central Chile and west-central Argentina by the Mapuche people (from ''mapu'' 'land' and ''che ...
) is used in South America and parts of Europe. 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
Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers ar ...
"), 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 the Tupi language
Old Tupi, Ancient Tupi or Classical Tupi (also spelled as Tupí) is an extinct Tupian language which was spoken by the aboriginal Tupi people of Brazil, mostly those who inhabited coastal regions in South and Southeast Brazil. It belongs to the ...
).
Taxonomy
The nutria was first described by Juan Ignacio Molina
Fr. Juan Ignacio Molina (; (June 24, 1740 – September 12, 1829) was a Chilean Jesuit priest, naturalist, historian, translator, geographer, botanist, ornithologist, and linguist. He is usually referred to as Abate Molina (a form of Abbot Moli ...
in 1782 as ''Mus coypus'', a member of the mouse
A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...
genus. The genus ''Myocastor'' was assigned in 1792 by Robert Kerr. Geoffroy Saint-Hilaire, independently of Kerr, named the species ''Myopotamus coypus'', and it is occasionally referred to by this name.
Four subspecies are generally recognized:
*''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
Chiloé Island ( es, Isla de Chiloé, , ) also known as Greater Island of Chiloé (''Isla Grande de Chiloé''), is the largest island of the Chiloé Archipelago off the west coast of Chile, in the Pacific Ocean. The island is located in southern ...
*''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.
Phylogeny
Comparison of DNA and protein sequences showed that the genus ''Myocastor'' is the sister group to the genus ''Callistomys'' (painted tree-rats). In turn, these two taxa share evolutionary affinities with other Myocastorini
Myocastorini is a tribe of echimyid rodents, proposed in 2017, and containing the five extant genera ''Callistomys'', ''Hoplomys'', ''Myocastor'', ''Proechimys'', and ''Thrichomys
''Thrichomys'' is a genus of South American rodents in the fam ...
genera: ''Proechimys'' and ''Hoplomys'' (armored rats) on the one hand, and ''Thrichomys'' on the other hand.
Appearance
The nutria somewhat resembles a very large rat
Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include ''Neotoma'' ( pack rats), ''Bandicota'' (bandicoot ...
, or a beaver
Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers ar ...
with a small, long and skinny hairless tail. Adults are typically in weight, and in body length, with a tail. It is possible for nutria to weigh up to , although adults usually average . Nutria have three sets of fur. The guard hairs on the outer coat are three inches long. 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 incisors. They have approximately 20 teeth with four large incisors that grow during the entirety of their lives. The orange discoloration is due to pigment staining from the mineral iron in the tooth enamel. Nutria have prominent four inch long whiskers on each side of their muzzle or cheek area. The mammary glands and nipple
The nipple is a raised region of tissue on the surface of the breast from which, in females, milk leaves the breast through the lactiferous ducts to feed an infant. The milk can flow through the nipple passively or it can be ejected by smooth mu ...
s of female nutria 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
The muskrat (''Ondatra zibethicus'') is a medium-sized semiaquatic rodent native to North America and an introduced species in parts of Europe, Asia, and South America. The muskrat is found in wetlands over a wide range of climates and habitat ...
(''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 coypus.
Life history
Nutria can live up to six years in captivity, but individuals uncommonly live past three years old. 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. 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 9 months. Once a female is pregnant, gestation
Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregna ...
lasts 130 days, and she may give birth to as few as one or as many as 13 offspring. Average nutria reproduction is four offspring. Female nutria 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. A female on average will have two litters a year.
They 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. Nutria have been known to be territorial and aggressive when caught or cornered. They will bite and attack humans and dogs when threatened. Nutria are mainly crepuscular or nocturnal, with most activity occurring around dusk and sunset with highest activity around midnight. When food is scarce, nutria will forage during the day. When food is plentiful, nutria will rest and groom during the day.
Distribution
Native to subtropical and temperate South America, it has been introduced to North America, Europe, Asia, and Africa, 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
Frostbite is a skin injury that occurs when exposed to extreme low temperatures, causing the freezing of the skin or other tissues, commonly affecting the fingers, toes, nose, ears, cheeks and chin areas. Most often, frostbite occurs in the han ...
on their tails, leading to infection or death. As a result, populations of nutrias often contract and even become locally or regionally extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
as in the Scandinavia
Scandinavia; Sámi languages: /. ( ) is a subregion#Europe, subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, ...
n countries and such US states as Idaho, Montana, and Nebraska during the 1980s. During mild winters, their ranges tend to expand northward. For example, in recent years, range expansions have been noted in Washington and Oregon, as well as Delaware.
According to the U.S. Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and ...
, nutria were first introduced to the United States in California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
, in 1899. They were first brought to Louisiana
Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is borde ...
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. The earliest account of nutria 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 nutria to escape into the wild. According to the Louisiana Department of Wildlife and Fisheries, nutria were also transplanted from Port Arthur, Texas
Port Arthur is a city in Jefferson County within the Beaumont–Port Arthur metropolitan area of the U.S. state of Texas. A small, uninhabited portion extends into Orange County; it is east of Houston. The largest oil refinery in the United Sta ...
, to the Mississippi River
The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it f ...
in 1941 and then spread due to a hurricane later that year.
Nutria are spreading rapidly in the U.S. state of Washington
Washington commonly refers to:
* Washington (state), United States
* Washington, D.C., the capital of the United States
** A metonym for the federal government of the United States
** Washington metropolitan area, the metropolitan area centered on ...
.
Habitat and feeding
Besides breeding quickly, each nutria consumes large amounts of vegetation. An individual consumes about 25% of its body weight daily, and feeds year-round. Being one of the world's larger extant rodents, a mature, healthy nutria averages in weight, but they can reach as much as . They eat the base of the above-ground stems of plants, and often dig through soil for roots and rhizomes
In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...
to eat. Nutria 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. Nutria eat the following plant varieties: cattail
''Typha'' is a genus of about 30 species of monocotyledonous flowering plants in the family Typhaceae. These plants have a variety of common names, in British English as bulrush or reedmace, in American English as reed, cattail, or punks, in A ...
, rushes, reeds, arrowheads
An arrowhead or point is the usually sharpened and hardened tip of an arrow, which contributes a majority of the projectile mass and is responsible for impacting and penetrating a target, as well as to fulfill some special purposes such as s ...
, flatsedges, and cordgrasses. Commercial crops that nutria also eat are lawn grasses, alfalfa, corn, rice, and sugarcane.
Nutrias are found most commonly in freshwater marshes and wetlands, but also inhabit brackish marshes and rarely salt marshes. They either construct their own burrows, or occupy burrows abandoned by beaver, muskrats, or other animals. They are also capable of constructing floating rafts out of vegetation. Nutria live in partially underwater dens. The main chamber is not submerged underground. Nutria are considered to be a species that lives in colonies. One male will share a den with three or four females and their offspring. Nutria 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.
Commercial use and issues
Farming and 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 nutria 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.[National Wetlands Research Center (June 2000), ''Nutria, Eating Louisiana's Coast'', United States Geological Survey] The first efficient and extensive nutria farms were located in South America in the 1920s. 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.
Nutrias were introduced to the Louisiana ecosystem in the 1930s, when they escaped from fur farms that had imported them from South America. Nutria were released into the wild by at least one Louisiana nutria farmer in 1933 and these releases were followed by E. A. McIlhenny
Edward Avery McIlhenny (March 29, 1872 – August 8, 1949), son of Tabasco brand pepper sauce tycoon Edmund McIlhenny, was an American businessman, explorer, bird bander and conservationist. He established a private wildlife refuge around his ...
who released his entire stock in 1945 on Avery Island. In 1940, some of the nutria escaped during a hurricane and quickly populated coastal marshes, inland swamps, and other wetland areas. From Louisiana, nutrias have spread across the Southern United States, wreaking havoc on marshland.
Following a decline in demand for nutria fur, nutria have since become pests in many areas, destroying aquatic vegetation, marshes, and irrigation
Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...
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. By the early 2000s, the Coastwide Nutria Control Program was established, which began paying bounties for nutria killed in 2002. In the Chesapeake Bay
The Chesapeake Bay ( ) is the largest estuary in the United States. The Bay is located in the Mid-Atlantic (United States), Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula (including the parts: the ...
region in Maryland
Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...
, where they were introduced in the 1940s, nutrias are believed to have destroyed of marshland in the Blackwater National Wildlife Refuge
The Blackwater National Wildlife Refuge was established in 1933 as a waterfowl sanctuary for birds migrating along the critical migration highway called the Atlantic Flyway. The refuge is located on Maryland's Eastern Shore, just south of C ...
. In response, by 2003, a multimillion-dollar eradication program was underway.["A Plague of Aliens"](_blank)
Feb/Mar 2003 edition of National Wildlife magazine, published by the National Wildlife Federation
The National Wildlife Federation (NWF) is the United States' largest private, nonprofit conservation education and advocacy organization, with over six million members and supporters, and 51 state and territorial affiliated organizations (includin ...
, article by Laura Tangley; accessed online December 8, 2006.
In the United Kingdom, nutrias were introduced to East Anglia
East Anglia is an area in the East of England, often defined as including the counties of Norfolk, Suffolk and Cambridgeshire. The name derives from the Anglo-Saxon kingdom of the East Angles, a people whose name originated in Anglia, in ...
, for fur, in 1929; many escaped and damaged the drainage works, and a concerted programme by MAFF MAFF may refer to:
* MAFF (gene), a transcription factor
* Malmö Arab Film Festival, held in Malmö (Sweden), the largest Arabic film festival in Europe
* Ministry of Agriculture, Fisheries and Food (United Kingdom), a former department of UK gov ...
eradicated them by 1989. However, in 2012, a "giant rat" was killed in County Durham
County Durham ( ), officially simply Durham,UK General Acts 1997 c. 23Lieutenancies Act 1997 Schedule 1(3). From legislation.gov.uk, retrieved 6 April 2022. is a ceremonial county in North East England.North East Assembly About North East E ...
, with authorities suspecting the animal was, in fact, a nutria.
Food products
There is only a small selection of game meat websites on the internet where you can purchase nutria meat for consumption. There are no restaurants that advertise nutria meat dishes currently. In 1997 and 1998, Louisiana attempted to educate the public to consume nutria meat. Nutria meat is leaner with a lower fat content and lower in cholesterol compared to ground beef. In an effort to encourage Louisianians to eat nutria, several recipes were distributed to locals and published on the internet. People in poor and rural Louisiana have trapped and consumed nutria meat for decades.
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. 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. A claimed environmentally sound solution is the use of nutria meat to make dog food treats.
In Kyrgyzstan and Uzbekistan, nutria (Russian and local languages Нутрия) are farmed on private plots and sold in local markets as a poor man's meat. 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. It appears on the menu as a burger, hotdog, dumplings, or wrapped in cabbage leaves, with the flavour being somewhere between turkey and pork.
Ecological impacts
Herbiviory and Habitat degradation
Nutria herbivory "severely reduces overall wetland biomass and can lead to the conversion of wetland to open water. " Unlike other common disturbances in marshlands, such as fire and tropical storms, which are a once- or few-times-a-year occurrence, nutria feed year round, so their effects on the marsh are constant. Also, nutria are typically more destructive in the winter than in the growing season, due largely to the scarcity of above-ground vegetation; as nutria search for food, they dig up root networks and rhizomes for food. While nutria are the most common herbivores in Louisiana marshes, they are not the only ones. Feral hogs, also known as wild boar
The wild boar (''Sus scrofa''), also known as the wild swine, common wild pig, Eurasian wild pig, or simply wild pig, is a suid native to much of Eurasia and North Africa, and has been introduced to the Americas and Oceania. The species is ...
s (''Sus scrofa''), swamp rabbit
The swamp rabbit (''Sylvilagus aquaticus''), also called the cane-cutter, is a large cottontail rabbit found in the swamps and wetlands of the southern United States. The species has a strong preference for wet areas, and it will take to the wate ...
s (''Sylvilagus aquaticus''), and muskrat
The muskrat (''Ondatra zibethicus'') is a medium-sized semiaquatic rodent native to North America and an introduced species in parts of Europe, Asia, and South America. The muskrat is found in wetlands over a wide range of climates and habitat ...
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 nutria 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. " Essentially, this means, as different factors were added together, the result was less overall vegetation. Adding fertilizer to open plots did not promote plant growth; instead, nutria 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.
Wetlands
A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...
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. These very biodiverse systems provide resources, shelter, nesting sites, and resting sites (particularly Louisiana's coastal wetlands such as 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. 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. The problem became so serious that Sheriff Harry Lee of Jefferson Parish Jefferson may refer to:
Names
* Jefferson (surname)
* Jefferson (given name)
People
* Thomas Jefferson (1743–1826), third president of the United States
* Jefferson (footballer, born 1970), full name Jefferson Tomaz de Souza, Brazilian foot ...
used SWAT
In the United States, a SWAT team (special weapons and tactics, originally special weapons assault team) is a police tactical unit that uses specialized or military equipment and tactics. Although they were first created in the 1960s to ...
sharpshooters against the animals.
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. The survey revealed through aerial surveys of transects that herbivory damage to wetlands totaled roughly . The next year, LDWF performed the same survey and found the area damaged by herbivory increased to about . The LDWF has determined the wetlands affected by nutria decreased from an estimated minimum of of Louisiana wetlands in 2002–2003 season to about during the 2010–2011 season. 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
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...
parasite
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
(''Strongyloides
''Strongyloides'' (from Greek ''strongylos'', round, + ''eidos'', resemblance), anguillula, or threadworm is a genus of small nematode parasites, belonging to the family Strongylidae, commonly found in the small intestine of mammals (particularl ...
myopotami'') that can infect the skin of humans, causing dermatitis similar to strongyloidiasis. The condition is also called "nutria itch". Other parasites they can host are tapeworms
Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of man ...
, liver fluke
Liver fluke is a collective name of a polyphyletic group of parasitic trematodes under the phylum Platyhelminthes.
They are principally parasites of the liver of various mammals, including humans. Capable of moving along the blood circulation, t ...
s, and blood flukes
''Schistosoma'' is a genus of trematodes, commonly known as blood flukes. They are parasitic flatworms responsible for a highly significant group of infections in humans termed ''schistosomiasis'', which is considered by the World Health Organi ...
. Waterbody contamination by nutria occurs through urine and feces. Nutria also host flea
Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about long, a ...
s, tick
Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...
s and chewing louse. They can carry several zoonotic diseases
A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a bacterium, virus, parasite or prion) that has jumped from a non-human (usually a vertebrate) to a human. ...
(diseases transmitted from animals to humans). They are reservoirs for salmonellosis, encephalomyocarditis virus
Cardiovirus A is a member of the ''Picornaviridae'' family. Infection with the virus causes encephalomyocarditis and reproductive disease in pigs. Although a variety of mammals may host the virus, pigs are classed as the domestic host as they are ...
, chlamydia psittaci
''Chlamydia psittaci'' is a lethal intracellular bacterial species that may cause endemic avian chlamydiosis, epizootic outbreaks in mammals, and respiratory psittacosis in humans. Potential hosts include feral birds and domesticated poultry, ...
and antibiotic resistant bacteria
A list of antibiotic resistant bacteria is provided below. These bacteria have shown antibiotic resistance (or antimicrobial resistance).
Enzyme NDM-1 (New Delhi Metallo-beta-lactamase-1)
NDM-1 is an enzyme that makes bacteria resistant to a ...
, Aeromonas
''Aeromonas'' is a genus of Gram-negative, facultative anaerobic, rod-shaped bacteria that morphologically resemble members of the family Enterobacteriaceae. Most of the 14 described species have been associated with human diseases. The most imp ...
spp. Other zoonotic disease of concern they are host reservoirs for are mycobacterium tuberculosis
''Mycobacterium tuberculosis'' (M. tb) is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, ''M. tuberculosis'' has an unusual, waxy coating on its c ...
, septicemia, toxoplasmosis
Toxoplasmosis is a parasitic disease caused by ''Toxoplasma gondii'', an apicomplexan. Infections with toxoplasmosis are associated with a variety of neuropsychiatric and behavioral conditions. Occasionally, people may have a few weeks or months ...
, and rickettsiosis
A rickettsiosis is a disease caused by intracellular bacteria.
Cause
Rickettsioses can be divided into a spotted fever group (SPG) and typhus group (TG).
In the past, rickettsioses were considered to be caused by species of Rickettsia. However, s ...
. According to the CDC
The Centers for Disease Control and Prevention (CDC) is the National public health institutes, national public health agency of the United States. It is a Federal agencies of the United States, United States federal agency, under the United S ...
, nutria carry two out of eight diseases of concern for the United States, rabies
Rabies is a viral disease that causes encephalitis in humans and other mammals. Early symptoms can include fever and tingling at the site of exposure. These symptoms are followed by one or more of the following symptoms: nausea, vomiting, vi ...
and salmonellosis. Nutria are considered a global alien species and have potential to spread disease to livestock and humans. Nutria are found on every continent except Australia and Antarctica. Native to the southern hemisphere and spreading globally requires preventive monitoring for zoonotic disease transmission. Currently nutria immigration is monitored for habitat destruction of wetlands, farmlands, marshes and is measured in habitat loss in acres. Increased local awareness of viral, bacterial and parasitic transmission from nutria to humans and livestock will be of greater importance as climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
progresses.
Control efforts
As a global alien species, nutria are monitored and managed throughout the world. Many countries have attempted eradication efforts with varying degrees of success.
Nutria are predicted to expand their range northward over the next century as global temperatures increase. As climate change progresses, eradication efforts will increase globally.
New Zealand
Nutrias are classed as a "prohibited new organism" under New Zealand's Hazardous Substances and New Organisms Act 1996
The Hazardous Substances and New Organisms Act (HSNO) is an Act of Parliament passed in New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North I ...
, preventing it from being imported into the country.
Great Britain
In the UK, nutria escaped from fur farms and were reported in the wild as early as 1932. There were three unsuccessful attempts to control nutria in east Great Britain 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. 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 nutria as possible near the Norfolk Broads. The campaign used live traps allowing non-target species to be released while any nutria caught were shot. Combined with cold winters in 1962 to 1963, almost 40,500 nutria 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 nutria in Great Britain. The trapping areas were broken into 8 sectors leaving no area uncontrolled. The 24 trappers were offered an incentive for early completion of the 10-year campaign. In 1989 nutria were assumed eradicated as only 3 males were found between 1987 and 1989.
European Union
This species is included since 2016 in the EU list of Invasive Alien Species of Union concern (the Union list). This implies that this species cannot be imported, bred, transported, commercialized, or intentionally released into the environment in the whole of the European Union.
Ireland
A nutria was first sighted in the wild in Ireland in 2010. Some nutria 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
Dublin (; , or ) is the capital and largest city of Republic of Ireland, Ireland. On a bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, bordered on the south by the Dublin Mountains, a part of th ...
via the Royal Canal
The Royal Canal ( ga, An Chanáil Ríoga) is a canal originally built for freight and passenger transportation from Dublin to Longford in Ireland. It is one of two canals from Dublin to the River Shannon and was built in direct competition ...
in 2019. Animals were found along the River Mulkear in 2015. The National Biodiversity Data Centre issued a species alert in 2017, saying that nutria " avethe potential to be a high impact invasive species in Ireland. This species is listed as among 100 of the worst invasive species in Europe."
Japan
Nutria were introduced to Japan in 1939. They were imported from France during World War II to support food shortages as well as the fur trade. After the war in 1950, many nutria were released en mass or escaped, and became one of Japan's worst invasive species, damaging river banks, rice fields and other valuable crops. In 1963 an eradication program was started to remove nutria but has shown little to no success. Nutria are still present in Japan and there is currently a restriction on importing, transporting and obtaining nutria per the Invasive Alien Species Act established in 2004.
United States
Nutria herbivory "is perhaps the least studied or quantified aspect of wetland loss". Many coastal restoration projects involve planting vegetation to stabilize marshland, but this requires proper nutria control to be successful.
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, only it is now under a different program title. Under the Coastwide Nutria Control Program, which also receives funds from CWPPRA
The Coastal Wetlands Planning, Protection and Restoration Act (CWPPRA) was passed by Congress in 1990 to fund wetland enhancement. In cooperation with multiple government agencies, CWPPRA is moving forward to restore the lost wetlands of the Gul ...
, 308,160 nutria were harvested the first year (2002–2003), revealing damaged and totaling $1,232,640 in incentive payments paid out to those legally participating in the program. Essentially, once a person receives a license to hunt or trap nutria, then that person is able to capture an unlimited number. When a nutria is captured, the tail is cut off and turned in to a Coastal Environments Inc. 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. Nutria harvesting increased drastically during the 2009–2010 year, with 445,963 nutria tails turned in worth $2,229,815 in incentive payments. 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 nutria across the Louisiana coast, and the LDWF combines these data with the results from the aerial surveys to determine the number of nutria remaining in the marshes and the amount of damage they are inflicting on the ecosystem.
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. 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".
Several desirable control methods are currently ineffective for various reasons. Zinc phosphide is the only rodenticide currently 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. 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 they could be 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. Contraception is not a common form of control, but is preferred by some wildlife managers. It also is 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. 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.
In Louisiana, a claimed environmentally sound solution is the killing of nutria to make dog food treats.
Atlantic coast
An eradication program on the Delmarva Peninsula, between Chesapeake Bay
The Chesapeake Bay ( ) is the largest estuary in the United States. The Bay is located in the Mid-Atlantic (United States), Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula (including the parts: the ...
and the Atlantic coast, where they once numbered in the tens of thousands and had destroyed thousands of hectares of marshland, had nearly succeeded by 2012. In September 2022 government officials announced that nutria have been completely eradicated on the Maryland Eastern Shore
The Eastern Shore of Maryland is a part of the U.S. state of Maryland that lies mostly on the east side of the Chesapeake Bay. Nine counties are normally included in the region. The Eastern Shore is part of the larger Delmarva Peninsula that ...
.
California
The first records of nutria invading California dates from the 1940s and 1950s, when the species was found in the agriculture-rich Central Valley and the south coast of the state, but by the 1970s the animals had been extirpated statewide. They were found again in Merced County in 2017, on the edge of the San Joaquin River Delta. State officials are concerned that they will harm infrastructure that sends water to San Joaquin Valley
The San Joaquin Valley ( ; es, Valle de San Joaquín) is the area of the Central Valley of the U.S. state of California that lies south of the Sacramento–San Joaquin River Delta and is drained by the San Joaquin River. It comprises seven c ...
farms and urban areas. In 2019, the California Department of Fish and Wildlife
The California Department of Fish and Wildlife (CDFW), formerly known as the California Department of Fish and Game (CDFG), is a state agency under the California Natural Resources Agency. The Department of Fish and Wildlife manages and protect ...
(CDFW) received nearly $2 million in Governor
A governor is an administrative leader and head of a polity or political region, ranking under the head of state and in some cases, such as governors-general, as the head of state's official representative. Depending on the type of political ...
Gavin Newsom
Gavin Christopher Newsom (born October 10, 1967) is an American politician and businessman who has been the 40th governor of California since 2019. A member of the Democratic Party, he served as the 49th lieutenant governor of California fr ...
's first budget, and an additional $8.5 million via the Delta Conservancy
Delta commonly refers to:
* Delta (letter) (Δ or δ), a letter of the Greek alphabet
* River delta, at a river mouth
* D (NATO phonetic alphabet: "Delta")
* Delta Air Lines, US
* Delta variant of SARS-CoV-2 that causes COVID-19
Delta may also r ...
(a state agency focused on the Delta) to be spent over the course of three years. The state has adopted an eradication campaign based on the successful effort in the Chesapeake Bay
The Chesapeake Bay ( ) is the largest estuary in the United States. The Bay is located in the Mid-Atlantic (United States), Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula (including the parts: the ...
, including strategies such as the " Judas nutria" (in which individualized nutria are caught, sterilized, fitted with radio collar
GPS animal tracking is a process whereby biologists, scientific researchers or conservation agencies can remotely observe relatively fine-scale movement or migratory patterns in a free-ranging wild animal using the Global Positioning System (G ...
s, and released, whereupon they can be tracked by hunters as they return to their colonies) and the use of trained dogs. The state has also reversed a prior "no-hunting" policy, although hunting the animals does require a license. California currently has a restriction on importation and transportation without a permit. If nutria are found or captured in the state of California, local authorities must be notified right away and the nutria cannot be released. Licensed hunters in the state of California may hunt nutria as a non-game animal. Eradication programs are not advised in California due to native species of muskrat and beaver being misidentified.
Gallery
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
Coypus.jpg, Feral nutria in Oise river in France
File:Myocastor coypus 2016 G2.jpg, 10-day-old baby nutria
References
Further reading
* Sandro Bertolino, Aurelio Perrone, and Laura Gola "Effectiveness of coypu control in small Italian wetland areas" Wildlife Society Bulletin Volume 33, Issue 2 (June 2005) pp. 714–72.
* 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. 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
Tulane University, officially the Tulane University of Louisiana, is a private university, private research university in New Orleans, Louisiana. Founded as the Medical College of Louisiana in 1834 by seven young medical doctors, it turned into ...
. New Orleans. 2006.
* 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
External links
* The documentary
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.
Saving the Bay: The History of the Chesapeake Bay Nutria Eradication Project
- USDA/Animal and Plant Health Inspection Service
Portland State University
- Report on nutrias in the Pacific Northwest of North America.
Species Profile - Nutria (''Myocastor coypus'')
National Invasive Species Information Center, United States National Agricultural Library. Lists general information and resources for nutria.
{{Authority control
Aquatic mammals
Articles containing video clips
Extant Piacenzian first appearances
Herbivorous mammals
Hystricognath rodents
Mammals described in 1782
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Mammals of Brazil
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Rodents of South America
Taxa named by Juan Ignacio Molina