The
coypu, or
nutria (
Myocastor coypus), is a large,
herbivorousA herbivore is an animal that is adapted to eat plants and not meat.Herbivory is a form of predation in which an organism consumes principally autotrophs such as plants, algae and photosynthesizing bacteria....
, semiaquatic
rodentRodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
and the only member of the family
Myocastoridae. Originally native to temperate
South AmericaSouth America is the southern continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere...
, it has since been introduced to
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
,
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
,
AsiaAsia is the world's largest and most populous continent, located in the eastern and northern hemispheres. It covers 8.6% of the earth's total surface area and with approximately 4 billion people, it hosts 60% of the world's current human population.Asia is traditionally defined as part of the...
, and
AfricaAfrica is the world's second-largest and second most-populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area. With a billion people in 61 territories, it accounts for about 14.8% of the...
, primarily by fur ranchers. Although it is still valued for its fur in some regions, its destructive feeding and burrowing behaviors make this
invasive species'Invasive species' is a phrase with several definitions. The first definition expresses the phrase in terms of non-indigenous species that adversely affect the habitats they invade economically, environmentally or ecologically...
a pest throughout most of its range.
There are two commonly-used names in the
English languageEnglish is a West Germanic language that developed in England during the Anglo-Saxon era. As a result of the military, economic, scientific, political, and cultural influence of the British Empire during the 18th, 19th, and early 20th centuries, and of the United States since the mid 20th century,...
for
Myocastor coypus.
The
coypu, or
nutria (
Myocastor coypus), is a large,
herbivorousA herbivore is an animal that is adapted to eat plants and not meat.Herbivory is a form of predation in which an organism consumes principally autotrophs such as plants, algae and photosynthesizing bacteria....
, semiaquatic
rodentRodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
and the only member of the family
Myocastoridae. Originally native to temperate
South AmericaSouth America is the southern continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere...
, it has since been introduced to
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
,
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
,
AsiaAsia is the world's largest and most populous continent, located in the eastern and northern hemispheres. It covers 8.6% of the earth's total surface area and with approximately 4 billion people, it hosts 60% of the world's current human population.Asia is traditionally defined as part of the...
, and
AfricaAfrica is the world's second-largest and second most-populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area. With a billion people in 61 territories, it accounts for about 14.8% of the...
, primarily by fur ranchers. Although it is still valued for its fur in some regions, its destructive feeding and burrowing behaviors make this
invasive species'Invasive species' is a phrase with several definitions. The first definition expresses the phrase in terms of non-indigenous species that adversely affect the habitats they invade economically, environmentally or ecologically...
a pest throughout most of its range.
There are two commonly-used names in the
English languageEnglish is a West Germanic language that developed in England during the Anglo-Saxon era. As a result of the military, economic, scientific, political, and cultural influence of the British Empire during the 18th, 19th, and early 20th centuries, and of the United States since the mid 20th century,...
for
Myocastor coypus. The name
nutria (or local derivatives such as "
nutria- or
nutra- rat") is generally used in North America and Asia; however, in
SpanishSpanish or Castilian is a Romance language in the Ibero-Romance group that originated in northern Spain and gradually spread in the Kingdom of Castile, evolving into the principal language of government and trade in the Iberian peninsula...
-speaking countries, the word
nutria refers to the
otterOtters are semi-aquatic fish-eating mammals. The otter subfamily Lutrinae forms part of the family Mustelidae, which also includes weasels, polecats, badgers, as well as others. With thirteen species in seven genera, otters have an almost worldwide distribution...
. To avoid this ambiguity, the name
coypu (derived from the
MapudungunMapudungun is a language isolate spoken in central Chile and west central Argentina by the Mapuche people. It is also known as Mapudungu, Mapuche, and Araucanian...
word
kóypu) is used in Latin America and Europe. In France, the coypu is known as a
ragondin. In Dutch it is known as
beverrat (beaver rat). In Italy, instead, the popular name is, like in North America and Asia,
nutria, but it is also called
castorino (
little beaverThe beaver is a primarily nocturnal, large, semi-aquatic rodent. Castor includes two extant species, Castor canadensis and Castor fiber . Beavers are known for building dams, canals, and lodges . They are the second-largest rodent in the world...
), by which its fur is known.
Taxonomy
The coypu was first described by
Juan Ignacio MolinaFr. Juan Ignacio Molina was a Chilean Jesuit priest, naturalist, historian, botanist, ornithologist and geographer.-Biography:...
in 1782 as
Mus coypus, a member of the
mouseA mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. The American white-footed mouse and the deer mouse also sometimes live in houses. In some places, certain kinds of field mice are also common...
or (tervanis) genus. The genus
Myocastor, assigned in 1792 by
Robert KerrRobert Kerr FRS was a scientific writer and translator from Scotland.Kerr was born in Roxburghshire as the son of a jeweller. He studied medicine at the University of Edinburgh and practised at the Edinburgh Foundling Hospital as a surgeon...
, is derived from the
GreekGreek , an independent branch of the Indo-European family of languages, is the language of the Greeks. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. In its ancient form, it is the language of classical...
mys and
kastor, or "mouse-beaver".
GeoffroyÉtienne Geoffroy Saint-Hilaire was a French naturalist who established the principle of "unity of composition". He was a colleague of Jean-Baptiste Lamarck and expanded and defended Lamarck's evolutionary theories...
, 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
- M. c. coypus: central Chile, Bolivia
- M. c. melanops: Chiloé Island
Chiloé Island , also known as Greater Island of Chiloé , is the largest island of Chiloé Archipelago off the coast of Chile, in the Pacific Ocean. The island is located in southern Chile, in the Los Lagos Region...
- M. c. santacruzae: Patagonia
Patagonia is a geographic region containing the southernmost portion of South America. Located in Argentina and Chile, it comprises the southernmost portion of the Andes mountains to the west and south, and plateaux and low plains to the east. The name Patagonia comes from the word patagón used by...
M. 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.
Appearance
The coypu somewhat resembles a very large
ratRats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...
. Adults are typically in weight, and in body length, with a 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
incisorIncisors are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below.-Function:...
teeth (unlike
ratRats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...
s, which have brownish yellow incisors). The
nippleIn its most general form, a nipple is a structure from which a fluid emanates. More specifically, it is the projection on the breasts of a mammal by which breast milk is delivered to a mother's young.-Anatomy:...
s of female coypu are high on her flanks. 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
muskratThe muskrat , the only species in genus Ondatra, is a medium-sized semi-aquatic rodent native to North America, and introduced in parts of Europe, Asia, and South America. The muskrat is found in wetlands and is a very successful animal over a wide range of climates and habitats...
. 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
herbivorousA herbivore is an animal that is adapted to eat plants and not meat.Herbivory is a form of predation in which an organism consumes principally autotrophs such as plants, algae and photosynthesizing bacteria....
, feeding on river plants, and live in burrows alongside stretches of water.
Commercial and environmental issues
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,
irrigationIrrigation is an artificial application of water to the soil. It is usually used to assist in growing crops in dry areas and during periods of inadequate rainfall...
systems, chewing through human-made items, such as tires and wooden house panelling in
LouisianaThe State of Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state divided into parishes, which are local governments equivalent to counties...
, eroding river banks, and displacing native animals. Coypu were introduced to
LouisianaThe State of Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state divided into parishes, which are local governments equivalent to counties...
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. In the
Chesapeake BayThe Chesapeake Bay is the largest estuary in the United States. It lies off the Atlantic Ocean, surrounded by Maryland and Virginia. The Chesapeake Bay's watershed covers in the District of Columbia and parts of six states: New York, Pennsylvania, Delaware, Maryland, Virginia, and West Virginia...
region in
MarylandMaryland is a state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia and the District of Columbia to the south and west, Pennsylvania to the north, and Delaware to the east. It is comparable in size to the European country of Belgium. According to the U.S...
, where they were introduced in the 1940s, coypu are believed to have destroyed of marshland in the
Blackwater National Wildlife RefugeThe 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 AngliaEast Anglia is a traditional name for a region of eastern England, named after an ancient Anglo-Saxon kingdom, the Kingdom of the East Angles. The Angles took their name from their homeland Angeln, in northern Germany. East Anglia initially consisted of Norfolk and Suffolk, but upon the marriage of...
, again for fur, in 1929; many escaped and damaged the drainage works, and a concerted programme by
MAFFThe Ministry of Agriculture, Fisheries and Food was a United Kingdom government department created by the Board of Agriculture Act 1889 and at that time called the Board of Agriculture....
eradicated them by 1989.
Coypu meat is lean and low in
cholesterolCholesterol is a lipidic, waxy steroid found in the cell membranes and transported in the blood plasma of all animals. It is an essential component of mammalian cell membranes, where it is required to establish proper membrane permeability and fluidity...
. 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
nematodeThe "roundworms" or "nematodes" are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 80,000 have been described, of which over 15,000 are parasitic. It has been estimated that the total number of...
parasite (
Strongyloides myopotami) that can infect the skin of humans causing dermatitis similar to
strongyloidiasisStrongyloidiasis is a human parasitic disease caused by the nematode Strongyloides stercoralis. Other Strongyloides include S...
. The condition is also called "nutria itch".
Distribution
The distribution of coypu tends to expand and contract with successive cold or mild winters. During cold winters, coypu often suffer
frostbiteFrostbite-is a condition that results in body tissues is frozen. the next step is hyporterma. is the medical condition wherein localized damage is caused to skin and other tissues due to extreme cold....
on their tails leading to
infectionAn infection is the detrimental colonization of a host organism by a foreign species. In an infection, the infecting organism seeks to utilize the host's resources to multiply, usually at the expense of the host. The infecting organism, or pathogen, interferes with the normal functioning of the...
or death. As a result, populations of coypu often contract and even become locally or regionally extinct (as in the
ScandinaviaScandinavia is a geographical region in northern Europe that includes, and is named after, the Scanian Province. It consists of the kingdoms of Norway, Sweden, and Denmark...
n countries during the 1980s). During mild winters, their ranges tend to expand northward.
External links