|Coypu or Nutria|
Fossil range: Late Pliocene - Recent
The coypu, or nutria (Myocastor coypus) is a large, herbivorous, semiaquatic rodent and the only member of the family Myocastoridae. Juan Ignacio Molina ( June 24, 1740 &ndash September 12, 1829) was a Chilean priest and naturalist. Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell Rodentia is an order of Mammals also known as rodents, characterised by two continuously-growing incisors in the upper and lower jaws which must Originally native to temperate South America, it has since been introduced to North America, Europe, Asia and Africa, primarily by fur ranchers. South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a  Although it is still valued for its fur in some regions, its destructive feeding and burrowing behaviors make this invasive species a pest throughout most of its range. Introduced species|Weed Invasive species is a phrase with several definitions A pest is an organism which has characteristics that are regarded by Humans as injurious or unwanted
There are two commonly-used names in the English language for Myocastor coypus. English is a West Germanic language originating in England and is the First language for most people in the United Kingdom, the United States The name nutria (or local derivatives such as "nutria- or nutra- rat") is generally used in North America and Asia; however, in Spanish-speaking countries, the word nutria refers to the otter. Otters are semi- aquatic (or in one case aquatic) fish-eating Mammals The otter subfamily Lutrinae forms part of the family To avoid this ambiguity, the name coypu (derived from the Mapudungun word kóypu) is used in Latin America and Europe. Mapudungun (from mapu 'earth land' and dungun 'speak speech' is a Language isolate spoken in central Chile and west central Argentina  In France, the coypu is known as a ragondin. In Dutch it is known as beverrat (beaver rat).
The coypu was first described by Juan Ignacio Molina in 1782 as Mus coypus, a member of the mouseor (tervanis) genus. Juan Ignacio Molina ( June 24, 1740 &ndash September 12, 1829) was a Chilean priest and naturalist. A mouse (plural mice) is a small Animal that belongs to one  The genus Myocastor, assigned in 1792 by Robert Kerr, is derived from the Greek mys and kastor, or "mouse-beaver". Robert Kerr FRS (1755 &ndash October 11, 1813) was a scientific Writer and Translator from Scotland. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly  Geoffroy, independently of Kerr, named the species Myopotamus coypus, and it is occasionally referred to by this name. Étienne Geoffroy Saint-Hillaire ( April 15, 1772 - June 19, 1844) was a French naturalist who established the principle
Four subspecies are generally recognized:
M. Llao LLaojpg|thumb|250px| Lake Nahuel Huapi, near Bariloche, Argentina c. bonariensis, the subspecies present in the northernmost (subtropical) part of the coypu's range, is believed to be the type of coypu most commonly introduced to other continents. 
The coypu somewhat resembles a very large rat in appearance. Rats are various medium sized long-tailed Rodents of the superfamily Muroidea Adults are typically 5–9 kg (10-20 lb) in weight, and 40–60 cm (15-24 inches) in body length, with a 30–45 cm (12-18 inches) tail. They have a coarse, darkish brown outer fur with a soft under-fur. Two distinguishing marks are the presence of a white patch on the muzzle, and webbed hind feet. They can also be identified by their bright orange-yellow incisor teeth (unlike rats, which have brownish yellow incisors). Incisors (from Latin incidere, "to cut" are the first kind of Tooth in Heterodont Mammals They are located in the Premaxilla Rats are various medium sized long-tailed Rodents of the superfamily Muroidea The nipples of female coypu are high on her flanks. In its most general form a nipple is a Structure from which a fluid emanates This allows their young to feed while the female is in the water.
Coypu can also be mistaken for another widely dispersed semi-aquatic rodent that occupies the same wetland habitats, the muskrat. The muskrat ( Ondatra zibethicus) the only Species in Genus Ondatra, is a medium-sized semi-aquatic Rodent native to North America The muskrat, however, is smaller, more tolerant of cold climates, and has a laterally flattened tail that it uses to assist in swimming, whereas the tail of a coypu is round.
They are herbivorous, feeding on river plants, and live in burrows alongside stretches of water. Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell
Local extinction in their native range due to overharvest led to the development of coypu fur farms in the late 1800s and early 1900s. 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 coypu often are released or escape as operations become unprofitable.
As demand for coypu fur declined, coypu have since become pests in many areas, destroying aquatic vegetation, irrigation systems, chewing through human-made items, such as tires and wooden house panelling in Louisiana, eroding river banks, and displacing native animals. Irrigation is an artificial application of water to the soil usually for assisting in growing crops The State of Louisiana ( or, État de Louisiane, pronounced) is a state located in the southern region of the United States of America Coypu were introduced to Louisiana in the 1930s for fur, for example, and nutria damage in Louisiana became so severe that in 2005, a bounty program was in effect to aid in controlling the animal. The State of Louisiana ( or, État de Louisiane, pronounced) is a state located in the southern region of the United States of America  In the Chesapeake Bay region in Maryland, where they were introduced in the 1940s, coypu are believed to have destroyed 7,000 to 8,000 acres (32 km²) of marshland in the Blackwater National Wildlife Refuge. The Chesapeake Bay is the largest Estuary in the United States. 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. In response, by 2003, a multi-million dollar eradication program was underway. 
Coypu were also introduced to East Anglia, again for fur, in 1929; many escaped and damaged the drainage works, and a concerted program by MAFF eradicated them by 1989. East Anglia is often used as a shorthand for the Kingdom of the East Angles.
Coypu meat is lean and low in cholesterol. For the play L'Avare by Molière see The Miser. Avaré is a city in the State Cholesterol is a Lipid found in the Cell membranes and transported in the Blood plasma of all Animals It is an essential component of mammalian While there have been many attempts to establish markets for coypu meat, all documented cases have generally been unsuccessful. Unscrupulous entrepreneurs have promoted coypu and coypu farms for their value as "meat", "fur", or "aquatic weed control". In recent years they have done so in countries such as the United States, China, Taiwan and Thailand. In every documented case the entrepreneurs sell coypu "breeding stock" at very high prices. Would-be coypu farmers find that the markets for their products disappear after the promoter has dropped out of the picture.
In the former Soviet republics of Central Asia, specifically Kyrgyzstan and Uzbekistan, Nutria (Russian and local languages Нутриа) are farmed on private plots and sold in local markets as a poor man's meat.
In addition to direct environmental damage, coypu are the host for a nematode parasite (Strongyloides myopotami) that can infect the skin of humans. The nematodes or roundworms ( Phylum Nematoda from Greek (nema "thread" + -ode "like" are one of the most common Parasitism is a type of symbiotic relationship between Organisms of different Species. When this happens the condition is called "nutria itch. "
The distribution of coypu tends to expand and contract with successive cold or mild winters. During cold winters, coypu often suffer frostbite on their tails leading to infection or death. Frostbite ( congelatio in Medical terminology) is the Medical condition whereby damage is caused to Skin and other tissues An infection is the detrimental Colonization of a host Organism by a foreign Species. As a result, populations of coypu often contract and even become locally or regionally extinct (as in the Scandinavian countries during the 1980s). In Biology and Ecology, extinction is the cessation of existence of a Species or group of taxa. Terminology and usage As a cultural term "Scandinavia" has no official definition and is subject to usage by those who identify with the culture in question as well During mild winters, their ranges tend to expand northward.