Nutria
| Nutria | ||||||||||||
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Nutria on the Ljubljanica river in Slovenia |
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| Systematics | ||||||||||||
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| Scientific name of the subfamily | ||||||||||||
| Myocastorinae | ||||||||||||
| Ameghino , 1904 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Myocastor | ||||||||||||
| Kerr , 1792 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Myocastor coypus | ||||||||||||
| ( Molina , 1782) |
The (rare: the) Nutria ( Myocastor coypus ), also coypu or rare Nutria , tail beaver , tail rat or coypu called, is one of South America originated and in Central Europe is settled rodent species . It is classified either in its own family, Myocastoridae, or as a subfamily Myocastorinae within the spiny rats (Echimyidae). According to recent molecular analyzes (based on homologous DNA sequences, mitochondrial and nuclear genes), the genus undoubtedly belongs to the Echimyidae. It is the only aquatic (semiaquatic) representative in a group of otherwise soil-living genera.
The nutria is sometimes with the one from North America coming muskrat confused, which is also in Europe as neozoon has established, however, is smaller and has a laterally flattened tail.
Occurrence
The original home of the nutria, which live on rivers, lakes, ponds and swamps, is subtropical and temperate South America. There it occurs from southern Brazil to Tierra del Fuego and was on the verge of extinction in the 19th century. Basically, the animals live very true to their location and are committed to defending their territory.
Nutrias are now considered naturalized in large parts of North America and Eurasia . The population in Eurasia is due to animals that have escaped from fur farms as well as to deliberate reintroductions. Keeping in Europe began around 1890 in France, the first farms in Germany existed since 1926. From around 1930, populations in Germany that go back to feral animals are expected. After the Second World War, the main buyer of nutria skins was the Federal Republic of Germany. Towards the end of the 20th century, interest in fashion in Germany also turned away from Nutriapelz, at the same time German fur sales fell considerably. Escaped animals were able to reproduce strongly due to the almost non-existent hunt.
The first animals came to the United States via fur farms in Louisiana in the 1930s. From there, due to the favorable local climate for nutrias and their high rate of reproduction , captive refugees very quickly established a population of millions. Targeted releases also occurred. There are isolated occurrences in Kenya ( Lake Naivasha ), Japan (south of Okayama ) and Western Australia .
In Germany, the nutria can be found in numerous bodies of water in all countries . There are larger and largely stable populations on the rivers Niers , Nidda , Schwalm and Cloer on the Lower Rhine and on the Spree and Saale in eastern Germany, especially in the Spreewald . Most of the time, the animals, especially in parks or on golf courses, are used to visits from walkers and can be fed vegetables without being too shy. A rapid spread does not take place in Germany, however, since Central Europe does not offer the feral farm animals an optimal climate. Some populations therefore collapse again after a few years. In Austria, the population is limited to isolated, usually short-lived populations that regularly do not survive harsh winters. The species is not permanently established there. Nutria is now also settling in the Czech Republic, for example at the confluence of the Elbe and Adler rivers .
Appearance
The nutria reaches a body length of up to 65 cm and weighs 8-10 kg when grown up. Their round, scale-covered, barely hairy tail has a length of about 30–45 cm. The animals are therefore smaller than adult beavers (maximum head-trunk length around 100 cm, trowel length approx. 35 cm, weight 25–30 kg). Male nutrias generally grow slightly larger than females. On the hind feet they each have between the first four toes webbed , the fifth toe is exposed. The orange color of the incisor teeth, which is caused by iron deposition, is also noticeable in adult animals.
Mussel eating
Webbed feet
floating
hide
The coat color is reddish brown, slightly grayish on the belly. Animals that have escaped from fur farms also show a number of color variants. They have light gray, dark gray, black, brown, reddish, yellowish or almost white fur colors.
teeth
The tooth formula differs from that of most rodents in that it has a premolar in addition to the molars . This is a characteristic feature of the guinea pig-like (Cavioidea), for which the following formula applies:
Tooth formula
Skull, incisor teeth
orange-colored incisors
Way of life
Nutrias are both diurnal and nocturnal, especially crepuscular . They are almost pure vegetarians and feed mainly on leaves, stems, roots of aquatic plants and root crops . Snails, worms and freshwater mussels are also less common. The animals live either in pairs or in communities of about 12 to 15 animals. These then usually include the parents and their own offspring. In their homeland they are mostly even colony-forming (= larger groups). They live monogamous and can reproduce at any time of the year. After a gestation period of 19 weeks, the female gives birth to 6 to 8 quite developed, well-sighted and fully hairy cubs that are sexually mature after 5 months. Two to three litters per year are possible. Buildings are self-dug earthworks in the bank area or “nests” made of long-leaved plants (reeds) and thinner sticks, the entrances of which, in contrast to the muskrat and the beaver, are above the waterline (distinguishing feature). Nutrias can live for over ten years. They don't hibernate.
use
The nutria is a fur supplier . The skins are valued mainly for their dense and extremely fine undercoat. To remove the rather unattractive upper hair, they are usually plucked or sheared. For fur usage see the main article nutria fur .
Nutrias were probably deliberately introduced into Germany at the beginning of the 18th century and released for use. At the beginning of the 19th century, the wild stocks were largely wiped out due to the very high prices achieved at the time for Nutri furs ( seal fur replacement ) through intensive hunting, with the increase in breeding and the later decline in demand for the velvety look in fur fashion, the population recovered.
The European population at that time still descended from South American wild animals. Compared to today's herds, which consist of offspring from long-standing breeding lines , they had significantly better survival abilities. It was not until the 1920s that nutrias imported from Argentina were successfully kept and bred in captivity. Between 1930 and 1940 there were a total of more than 1,000 nutria farms in Germany, which supplied almost 100,000 pelts annually. Because of the Second World War , this still young branch of industry declined sharply, but gained strength again in the 1950s, and then practically disappeared completely in Germany until today - mainly due to fashion.
Further applies Nutriafleisch as very tasty, occasionally (derived from Sumpfbiber) as "Beaver" on the menu. In 1958 it said, “The meat of the nutria is valued as a luxury food, especially in South America by the local population and the hunters. It is very tender and tasty. The taste is about the same as suckling pig . In addition, the Argentinian government tried to increase the consumption of nutria meat in order to increase the profitability of farm breeding. ”Around 1967, 60,000 nutria pelts were produced annually in the GDR for commercial use, with 180,000 kilograms of meat being produced at the same time. A specialist book for fur breeders in the GDR from 1953 describes the processing of meat into roulades , Mettwurst , cooked salami and by means of smoking into country hunters . Also in the prisons of the GDR there was nutria with jacket potatoes . According to his information, a nutria farmer on the banks of the Wipfra received 24 euros for a kilo of nutria meat in 2015, and only one euro for a coat.
Not only in parts of North America have released nutrias become a real plague, in Louisiana the consumption of nutrias was advertised with a cost of US $ 2.1 million to "eat the plague". In Germany, too, there are always considerations.
Before eating nutria meat, a trichinae inspection is compulsory in Germany . However, in February 2020 it was announced from circles of the Federal Ministry of Food and Agriculture (BMEL) that a change to the Food Hygiene Ordinance was planned. Nutrias would then no longer necessarily have to be examined for trichinae when these changes come into force, as has been the case up to now. When asked, a spokesman for the Federal Ministry stated that a study carried out by the Federal Institute for Risk Assessment had come to the conclusion that trichinae findings in wild bog beavers are not known.
Damage
The nutria stocks in Germany doubled between 2006 and 2016. The nutria causes considerable damage to hydraulic engineering systems as it undermines dykes and bank areas. It also damages bank cane by feeding, which restricts the habitats of rare species. The cavities created by Nutrias are very large, and the resulting collapses in the ground can also endanger car traffic.
On the positive side, nutrias are pushing back muskrats, which are also naturalized (which cause considerable damage to the waterways), and their populations are easier to control. The nutria has been added to the list of invasive alien species of Union concern for the European Union , which prohibits further importation and breeding.
The Netherlands has stepped up the hunt for nutrias because of the threat to their dykes . In Lower Saxony, an increase in hunting is being discussed after the population increased from 4,000 to 24,000 animals between 2013 and 2016. In doing so, consideration is also being given to lifting the parent animal protection that is otherwise common in hunting . In the Netherlands, the fight against nutria and muskrat is organized by the water associations with permanent catchers to prevent dams and dykes from being damaged. There the population of nutrias was removed inland. Immigrant animals are still caught on the borders with Germany and on the large rivers.
In Lower Saxony, the closed season for the nutria has been lifted with effect from April 25, 2018. This does not affect the parent animal regulation (mother animal protection) according to Section 22 (4) of the Federal Hunting Act.
literature
- Mario Ludwig, Harald Gebhard, Herbert W. Ludwig, Susanne Schmidt-Fischer: New animals and plants in the natural environment. Recognize and identify immigrant species . BLV, Munich et al. 2000, ISBN 3-405-15776-5 .
- Johannes Klapperstück: The swamp beaver. (Nutria). (= Die Neue Brehm-Bücherei. Volume 115). 3rd, unchanged edition, reprint of the 2nd edition from 1964. Westarp-Wissenschaften-Verlags-Gesellschaft, Hohenwarsleben 2004, ISBN 3-89432-162-8 .
- Lauren E. Nolfo-Clements: Seasonal variations in habitat availability, habitat selection, and movement patterns of Myocastor coypus on a subtropical freshwater floating marsh. New Orleans LA 2006, (New Orleans LA, Tulane University, PhD thesis, 2006).
- Caroline Biela: The nutria (Myocastor coypus Molina 1782) in Germany - ecological causes and consequences of the spread of an invasive species. Munich 2008, (Munich, Technical University, diploma thesis, 2008), (PDF file; 6.68 MB) .
Web links
- Myocastor coypus in the endangered Red List species the IUCN 2006. Posted by: Pearson, 1996. Retrieved on 12 May, 2006.
Individual evidence
- ↑ Thomas Galewski, Jean-François Mauffrey, Yuri LR Leite, James L. Patton, Emmanuel JP Douzery: Ecomorphological diversification among South American spiny rats (Rodentia; Echimyidae): a phylogenetic and chronological approach. In: Molecular Phylogenetics and Evolution. Vol. 34, No. 3, March 2005, ISSN 1055-7903 , pp. 601-615, doi : 10.1016 / j.ympev.2004.11.015 .
- ↑ Erich Bettag: On the status of immigration and distribution of nutria in Rhineland-Palatinate. In: Mainz natural science archive. Supplement 10, 1988, ISSN 0174-6626 , pp. 22-26, quoted from: Daniel Scheide: Ecology, distribution, damage and management of “Myocastor coypus” in Germany in an international comparison. , ISBN 978-3-656-31835-4 (Trier, University, diploma thesis, 2012).
- ↑ Harald Gebhardt: Ecological and economic consequences of introductions of exotic wildlife (birds and mammals) in Germany. In: Wildlife Biology. Vol. 2, No. 3, 1996, ISSN 0909-6396 , pp. 205-211, abstract .
- ↑ Ruth M. Wallner (Red.): Aliens. Neobiota in Austria (= Austria. Federal Ministry for Agriculture, Forestry, Environment and Water Management. Green series of the Ministry of Life. Vol. 15). Böhlau, Vienna et al. 2005, ISBN 3-205-77346-2 , p. 111.
- ↑ a b c d Josef H. Reichholf : Mammals. (140 European species). Mosaik-Verlag, Munich 1983, ISBN 3-570-01182-8 (new, edited special edition, 5th print. Ibid. 1996, ISBN 3-576-10565-4 ), pp. 120-121: Art monograph Nutria.
- ↑ George A. Feldhamer, Bruce C. Thompson, Joseph A. Chapman (Eds.): Wild Mammals of North America. Biology, Management and Conservation. 2nd edition, revised. Johns Hopkins University Press, Baltimore MD et al. 2003, ISBN 0-801-87416-5 , p. 1134, limited preview in the Google book search.
- ↑ Paul Schöps, Herbert Grüner, Kurt Häse, Franz Schmidt: Fellwerk vom Sumpfbiber (Nutria). In: The fur trade. Writings for fur customers and the fur industry. NF Vol. 9, 1958, ZDB -ID 1008085-5 , pp. 202-206, here p. 204.
- ↑ Horst Keil: The trade in raw fur fur . Institute for the collection and purchase of agricultural products, Berlin 1967, p. 16.
- ↑ Kurt Kempe: The fur animal book. 2nd, expanded edition. Deutscher Bauern-Verlag, Berlin 1952, pp. 36–38.
- ↑ Hartmut Kaschka, Frank Zauritz: “My wall is still standing” . In: Bild - special edition on November 9, 2014, Axel Springer Verlag, p. 16 (quote from the female murderer Werner H., who has been incarcerated since 1980).
- ↑ Ulrike Nimz: The Nageprobe. In Süddeutsche Zeitung , 29./30. August 2015, p. 53. Note: Name of the breeder (over 60 animals) Edgar Heyder. Last accessed on September 28, 2015.
- ^ Working group Neozoa - General and Special Zoology University of Rostock: New Animals In Germany - Profiles.
- ↑ Establish new food - Fancy a nutria burger? In: Deutschlandfunk Nova . 25th September 2017 .
- ↑ Hannah Reutter: Nutria: In future no more compulsory trichinae examination . Jagderleben , February 29, 2020. Retrieved July 27, 2020.
- ↑ DJV: Nutria conquer Germany in: AFZ - Der Wald, issue 13/2017
- ↑ a b Many experts call for increased hunt for nutria in: Rundblick, Political Journal for Lower Saxony, Issue 165, Hanover, September 20, 2018
- ↑ List of Invasive Alien Species of Union Concern (PDF) accessed on July 15, 2016
- ↑ Dolf Moerens, Daan Bos: Intense fighting muskrat and nutria in the Netherlands. Nature in NRW 4/2018: 17-21
- ↑ Hunters' Association Stade: What Hunters Need to Know - Closed season for nutria from April 25, 2018 all year round . May 1, 2018. Last accessed January 5, 2019.