European beaver

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European beaver
European beaver (Castor fiber)

European beaver ( Castor fiber )

Systematics
Subclass : Higher mammals (Eutheria)
Superordinate : Euarchontoglires
Order : Rodents (Rodentia)
Family : Beaver (Castoridae)
Genre : Castor
Type : European beaver
Scientific name
Castor fiber
Linnaeus , 1758

The European beaver ( Castor fiber ), also known as the Eurasian beaver , is the largest rodent in Europe . It reaches a head-trunk length of 80 to 102 cm and a tail length of up to 35 cm. Adult European beavers weigh between 23 and 30 kg. Like all beavers , they live semi- aquatic and inhabit bodies of water and their bank areas. They actively shape their living spaces and eat purely plant-based.

Features and special features

European beaver with orange teeth

Adult European beavers weigh between 23 and 30 kg and have head-to-trunk lengths of 83 to 102 cm and tail lengths of 30 to 35 cm. Accordingly, the total lengths are 113-137 cm. The body is plump and stocky and increases in size towards the back. The head is short, wide and flattened at the top so that it merges directly into the strong neck muscles and trunk. The eyes and ears, which are arranged very high up, as well as the nose are above water even when the body is submerged. A nictitating membrane protects the eye when diving .

Front and rear legs are short. The front feet are designed to be gripped and have five fingers. The hind feet are large and have webbed toes, the second hind foot toe has a double claw for grooming the fur. The very dense fur is gray to dark brown or black on the upper side, and lighter on the underside. The hair density is on the abdomen ( ventral ) with 23,000 hairs / cm² higher than on the back (dorsal) with 12,000 hairs / cm². The wool hairs hold the air in the fur when diving and thus create effective insulation. The guard hairs , which get wider towards the end, protect the wool hair from water penetration. The tail (also called the trowel) is flat, broad, hairless and covered with scales. It serves as a control, driving mechanism and fat depot. The trowel is hit hard on the surface of the water to warn other members of the same species against enemies.

The European beaver (like all rodents ) has enlarged and constantly growing incisors. As in all land mammals, the tooth enamel consists largely of the inorganic hydroxyapatite . In addition to calcium , magnesium and other ionic compounds, the front of the teeth is additionally reinforced with iron and iron compounds, which is why the front of the teeth are often orange-red. These iron compounds are missing on the back of the teeth, which means that the front of the teeth is much harder and does not wear out as quickly as the back of the teeth. When gnawing at wood, this leads to a natural self- sharpening effect , which is used, among other things, in bionics for shredding. In contrast to the four incisor teeth, the sixteen molars of the beaver do not grow back for life, but - as in humans - are changed from deciduous teeth to permanent teeth.

The sexes of the European beaver hardly differ externally. Only suckling females can be recognized as such by their larger teats; otherwise the cloaca must be scanned for a penis bone . Eurasian and Canadian beavers are also difficult to distinguish externally.

distribution

Total area and stock development

Distribution of the European beaver
Beavers in Europe except Russia in 2003

The European beaver was originally native to large parts of Eurasia and inhabited a wide strip between Scandinavia and southern France as far as Siberia and south-western Mongolia. Direct persecution and habitat destruction led to widespread extermination across Europe up to the first half of the 20th century . In the European area it was only able to stay in four isolated residual areas: the middle Elbe , lower reaches of the Rhone , southern Norway and in the catchment area of ​​the Beresina up to the upper reaches of the Dnepr .

As early as 1714, the Prussian King Friedrich Wilhelm I issued an order to protect the beaver and encourage its reproduction "by avoiding arbitrarily harsh punishment". In the middle of the 19th century there were no more beavers anywhere else on the Upper Rhine . At the end of the 19th century, large parts of Germany and Europe were beaver-free. Both in Germany and in other European countries, protection programs were implemented from the first half of the 20th century and beavers were naturalized again. Animals of different subspecies (including foreign ones) were settled, and Canadian beavers were also settled locally , for example in Finland, Germany and Austria. Due to protective measures and natural expansion, the original area is now populated again, but the stocks are patchy. Natural occurrences now exist in Belarus , China , Germany , Kazakhstan , Mongolia , Norway and Russia . Eurasian beavers were reintroduced in Austria , Belgium , Croatia , the Czech Republic , Denmark , Estonia , Finland , Hungary , Italy , Latvia , Liechtenstein , Lithuania , Montenegro , the Netherlands , Poland , Romania , Serbia , Slovakia , Slovenia , Spain , Sweden , Switzerland , Ukraine and the United Kingdom . Based on re-naturalizations in Belgium, the Eifel and Saarland, Luxembourg was also repopulated around 2004 . The origin of the beaver in Bulgaria is unclear. The species became extinct in Moldova , Portugal and Turkey . The IUCN estimates the total number of beavers in Europe and Asia to be at least 639,000 animals. The population in Asia is still small.

Today's distribution in German-speaking countries

In Germany there are now more than 30,000 beavers again spread across all federal states. He has partly re-opened his territories through migration, but partly he was also resettled through targeted projects (partly Canadian beavers). The densest distribution areas are along the Elbe and its tributaries in the federal states of Saxony-Anhalt (core occurrence of the autochthonous Elbe beavers), Saxony, Lower Saxony, Brandenburg and Mecklenburg-Western Pomerania. The Bavarian population, which can be traced back to naturalizations of European beavers of mixed origins, is comparatively large. It is assumed that there are 20,000 animals in around 5,500 territories. In Baden-Württemberg, its number increased from 1,000 to 3,500 between 2008 and 2016. There are smaller stocks. a. in the Spessart , also in Berlin , the beaver is now at home again. The beaver has been resettled in Thuringia since 2007 and has since spread there along the Saale and its tributaries. In 2019, a population of around 300-400 animals can be assumed.

In Switzerland the beaver was exterminated through intensive hunting at the beginning of the 19th century. In 2008 there were around 1,600 beavers again due to reintroductions that started in 1957 and ended in 1977. A total of 141 beavers from Norway, France and Russia were released in Switzerland. The beavers are mainly found in the cantons of Thurgau , Zurich , Aargau , Freiburg , Waadt , Solothurn , Wallis and in the canton of Zug ( Lorze and Reuss Plain ).

In Austria the beaver was naturalized again between 1967 and 1985. More than 45 beavers were released in the Danube - March- Auen, where they reproduced well and where the main area of ​​distribution is still today. Some of the beavers released were Canadian beavers, but they were later caught again - as far as possible. Today it is believed that no Canadian beavers live in these areas anymore. Further animals were released in Upper Austria and Salzburg in 1972 and 1983 or immigrated from Bavaria and formed a second population in the Inn - Salzach Valley. Both populations grew together in 2003. A total of around 2,000 beavers lived in Austria in 2003, and between 2,800 and 3,000 beavers in 2006.

Swimming beaver

Way of life

Social behavior and reproduction

Elbe beaver

Beavers are monogamous, they enter into a single marriage for life. Only when one of the partners dies does the surviving beaver look for a new partner. They live in small family groups that consist of their parents and their one- and two-year-old cubs. At the age of two to three years, beavers become sexually mature and leave the family unit. If the capacity of the living space is sufficient, they will settle in the immediate vicinity of their parents. If all potential areas are occupied, it often comes to biting, the young beavers then try to develop new habitats on the water. Beavers mate underwater between January and April. After a gestation period of 105-109 days, two to three boys are born at the end of April, beginning of May, and more rarely up to six. These are fully hairy and can see ( fleeing nest ). The beaver cubs are suckled for around two to two and a half months. You start eating plant foods as early as eight days. The boys stay in the building up to the age of four to six weeks, after which they go on their first excursions accompanied by their parents or older siblings. You can already swim but have yet to learn to dive.

Diet of the beaver

Beavers are pure herbivores and use the most common plant species in their habitat. During the vegetation period, in addition to young shoots and leaves of softwood, they also regularly pick up grasses and herbaceous plants. Beavers neither hibernate nor hibernate , but are also active and foraging in winter in water and on land. In winter, their food consists mainly of softwood. The proven food spectrum includes 150 herbaceous plant species and 63 woody species. The food is primarily sought in the shoreline as well as on and in the water. Smaller trees that can be easily pulled out of the stand are preferred. Trees with a trunk diameter of no more than 8 cm are predominantly used, and it is often less than 3 cm. Felled trees are limbed, cut into pieces and taken to the beaver den. There they are often used as construction timber or food supplies (food rafts).

Much of the beaver's diet consists of plant fibers, the main component of which is cellulose , which mammals cannot break down in the intestines themselves. The symbiotic bacteria capable of doing this live in herbivorous rodents such as beavers in enlarged caecum. The contents of the caecum, made up of partially broken down cellulose, bacterial proteins, vitamins and enzymes, are immediately absorbed by the beaver after excretion ( caecotrophy ). The actual solution consists of indigestible wood residues.

Build dams and canals

European beavers build burrows on banks of water. These structures always have entrances that are below the surface of the water and consist of several tubes that lead into a living boiler above the water. The buildings have a ventilation pipe to the outside, but are otherwise closed, well insulated and dry. If the floor or ceiling becomes too thin, additional material (branches, stones, mud) is piled up. This construction method creates the typical “beaver castles”, which are often inhabited by several generations. Long-lived castles can reach diameters of up to 12 m and heights of up to 2 m. In the buildings z. B. also muskrats , shrews or grass snakes .

With the help of dams, the beaver dams watercourses to keep the entrances under water. The damming also allows it to transport wood more easily. Small dams are built from twigs, reeds and herbaceous plants and earth. Longer dams are built using pieces of young trees and twigs mixed with finer material. With the help of the dams, the beaver is able to actively regulate the water level in its territory. In beaver territories that have been occupied for a long time, there are usually no trees in the vicinity of the beaver den. These were felled and processed over time. The beaver can only transport more wood on the water. That is why he digs up to 500 m long canals (waterways) on which he transports tree trunks and branches to his building. This means that river systems can be diverted by the beaver and entire lakes (including the beaver lake) can be drained.

Predators and parasites

The natural predators of adult beavers (wolf, bear) are almost completely absent in Central Europe today. The small and helpless young animals are u. a. captured by dogs, large birds of prey (sea eagles) and large predatory fish such as pike and catfish. Like all wild animals, European beavers are inhabited by numerous endo- and ectoparasites. So are the intestinal tract and internal organs z. B. infested by flukes and roundworms . The beaver beetle ( Platypsyllus castoris , also inexactly called "beaver flea") lives in the fur of the beaver. It lives there on skin flakes, possibly also on skin secretions and wound fluid and is therefore regarded as commensal . Only the larvae can possibly cause superficial abrasions with their sharp mandibles , which would fulfill the criterion of an ectoparasite. An ectoparasite of the beaver is the beaver mite ( Schizocarpus mingaudi ). Like the beaver, both species are adapted to the semi-aquatic way of life.

Importance of landscaping

As an important animal builder, the beaver has a great influence on the design of the landscape. The changes in the water body often allow species of flowing and standing water to coexist. While types of flowing water may disappear due to lower flow speeds, oxygen saturation or higher temperatures, the inhabitants of slow-flowing or stagnant waters benefit. Overall, the diversity of species and the number of individuals, especially of invertebrates in beaver lakes, are increasing significantly. The impact of beaver dams on the fish fauna is less clear. While beaver dams can make migration of adult fish more difficult, especially in times of little rain, juvenile fish find better hiding places thanks to the branches felled by beavers, and the larger number of invertebrates also provides a better nutritional basis. Overall, ecologists see an improvement for the fish world, including the fish species used by humans.

The changes in the water and land habitat created by beavers are of great importance for amphibians and can make an important contribution to understanding their habitat requirements and distribution patterns. Through flooding and felling work, the beaver creates natural forest clearings over the long term, which were of great importance for biodiversity, especially in the wooded primeval landscape, for example, sedge beds are created by silting up or meadows when the dam is lost. These offered the people favorable conditions for primitive agriculture. Grass hay is also said to have been used on beaver meadows. Many plant species in today's wet grassland are likely to have their primary habitats in beaver meadows, such as meadowsweet and cabbage thistle . Also types of humid (e.g. pipe grass ) and dry (common oats and others) grassland communities are and were to be found there.

Family relationships

In addition to the European / Eurasian, the Canadian beaver ( Castor canadensis ) also belongs to the beaver family . Both species differ in the number of their chromosomes (European beaver 48, Canadian beaver 40). They each formed several subspecies during the Ice Ages. More than twenty subspecies have been described for the European beaver, which are recognized depending on the source:

  • Castor fiber fiber L., 1758 (Scandinavian beaver)
  • C. f. albicus Matschie, 1907 (Elbe beaver)
  • C. f. galliae Geoffroy, 1803 (Rhonebiber)
  • C. f. vistulanus Matschie, 1907 (Byelorussian beaver)
  • C. f. pohlei Serebrennikov, 1929 (Uralbiber)
  • C. f. birulai Serebrennikov, 1929 (Mongolian beaver)
  • C. f. tuvinicus Lavrov, 1969
  • C. f. belorussicus Lavrov, 1981
  • C. f. orientoeuropaeus Lavrov, 1981

The Elbe beaver Castor fiber albicus is the native subspecies of the beaver in Germany. It is mainly found in Germany, in Denmark and the Netherlands there are other occurrences. The total population of Castor fiber albicus was estimated at 6,000 animals in 2002 and is therefore relatively small. Germany, in particular the federal states of Saxony-Anhalt, Brandenburg, Mecklenburg-Western Pomerania and Saxony, has a great responsibility for the conservation of this subspecies.

In the Handbook of the Mammals of the World , which has been a reference since 2016 , however, no subspecies of the European beaver are recognized. According to this, there is a western and an eastern phylogroup within the species, which, however, cannot be viewed as independent subspecies.

Man and beaver

Tracking the beaver in historical times

Hunting beavers, 1695

As a result of the Council of Constance (1414-1418), a medieval papal edict defined the beaver as partially belonging to the fish because of its flat, scaled tail and its amphibious way of life. This allowed the beaver meat to be eaten from the hind legs on fasting days.

The thick beaver fur was in great demand and led to intensive hunting. Hats were made from the particularly waterproof fur, and hats, gloves and stockings were made from the hair. Bibergeil , the fragrance with which beavers mark their territories, was even more popular . It was regarded as an extremely effective remedy in medicine and was paid dearly. It has been used for nerve disorders, body aches and pains, and menstrual cramps. Due to the nutrition of bark and roots, various groups of active ingredients also used in modern medicine accumulate.

In the Lithuanian Statute (Chapter 9, Paragraph 9) of 1529, the beaver castle was placed under special protection: In the vicinity of a stick throw away from the beaver castle, neither plowing nor mowing nor wood was allowed. The beaver was subject to a heavy penalty for evicting or even killing or stealing the beaver. After a few centuries, silted beaver ponds often offered excellent arable land.

Tree felled by beavers in Norway

Today's conflicts

Beavers are not always welcome in the cultural landscape. Their very active habitat design can lead to conflicts with landowners. Common conflicts are:

  • Undermining of bank areas and driveways (risk of break-ins)
  • Undermining protective water structures (dams)
  • Undermining saddled ponds (fish ponds, extinguishing water ponds)
  • Blockage by driftwood (weir and mill passages, sewage treatment plants, etc.)
  • Waterlogging (agriculture and forestry, settlement area)
  • Flooding of infrastructure (basements, etc.)
  • Overflow of water intake points
  • Impairment of gardens and leisure facilities

In countries such as Germany , Austria and Switzerland , the activities of the strictly protected beaver are monitored. Management plans in nature and species protection provide a range of countermeasures to minimize conflicts with people. Beaver management includes public relations work, population monitoring, preventive and acute measures and, in some cases, aid for financial losses for property owners.

Hazard and protection

A so-called beaver ramp enables the animals to overcome man-made obstacles without leaving the vicinity of the water

Occasionally, beavers drown in extreme floods, this danger exists especially in developed waters, in which there are no islands and ledges to save. Infections from bite wounds are often fatal in polluted waters. Detergents contained in wastewater reduce the heat-insulating effect of the fur. Unsecured locks and propellers often lead to death. Young beavers are occasionally killed during muskrat hunt. Beavers also drown in fish traps and become victims of road traffic.

Due to water development and intensive land use, there is often a lack of suitable beaver habitats.

In resettlement programs, European beavers were removed from various populations in Germany, France, Scandinavia and Russia in order to build up new populations, for example in the Netherlands, Austria or Switzerland. This allows animals of subspecies such as the Elbe beaver ( Castor fiber albicus ), which have arisen through centuries of geographical isolation and whose populations often consisted of only a few specimens, to cross with each other again .

An essential contribution to the protection of the European beaver consists in securing and restoring its habitats in floodplains and glacial valleys. Species protection programs exist in Brandenburg and North Rhine-Westphalia, among others.

Sign for beaver protection on the Pegnitz in the city center of Nuremberg

This species is protected at European level by the Bern Convention, and in the EU member states it is also listed in Annex II and IV of the Habitats Directive . According to Article 3, Paragraph 1 of this Directive, the Member States must designate protected areas for the Natura 2000 network for habitats of this type and ensure the continuation or, if necessary, the restoration of a favorable conservation status. In addition, there is strict species protection in accordance with Articles 12, 14, 15 and 16 of the Directive, as for all species listed in Annex IV. The Estonian, Latvian, Lithuanian, Finnish, Swedish and Polish populations are exempt from strict protection and are listed in Appendix V.

Legal protection status (selection)

Red list classifications (selection)

  • Red List Federal Republic of Germany: V - Warning List
  • Red list of Switzerland: CR (Critically Endangered = threatened with extinction)
  • IUCN red list (worldwide or Eurasia): LC (Least Concern = not endangered)

literature

  • Christof Angst: Living with the beaver. Inventory survey 2008; Perspectives for dealing with the beaver in Switzerland . Environmental Knowledge No. 1008. Federal Office for the Environment , Bern, and Swiss Center for the Cartography of Fauna, Neuchâtel, 2010; ( online ).

Web links

Commons : European beaver  album with pictures, videos and audio files

Individual evidence

  1. ↑ a b c d e f g h i j k l m Rainer Allgöwer (2005): Biber Castor fiber Linnaeus, 1758. In: Die Säugetiere Baden-Württembergs Volume 2, pp. 181-189. ISBN 3-8001-4246-5
  2. ↑ a b Gerold Stocker: Beaver (Castor fiber L.) in Switzerland . Federal Institute for Forest Research, August 1985. P. 12. Stocker refers to: Tevis, L, 1950: Summer behavior of a family of beaver in New York State ; and on: Aleksiuk, M., 1970b: The function of the tail as a fat storage depot in the beaver (Castor canadensis Kuhl).
  3. ↑ a b Beaver lexicon beaver fur - Hello beavers! In: hallobiber.ch. Retrieved December 8, 2018 .
  4. ↑ Naturschutzverband Niedersachsen, Biologische Schutzgemeinschaft Hunte Weser-Ems together with the Naturschutzring Dümmer and the NaturschutzForum Deutschland - NaFor. March 2009. ISSN  0947-9503 . Retrieved June 26, 2011.
  5. ↑ http://biber-rlp.de/?page_id=101 ( Memento from May 12, 2012 in the Internet Archive )
  6. ^ Center Suisse de Cartographie de la Faune: Information on the beaver: teeth. (No longer available online.) In: cscf.ch. Archived from the original on August 8, 2013 ; Retrieved July 1, 2013 .
  7. ↑ Uwe Vaartjes: The beaver's teeth. (PDF): zfmk.de . April 1, 2008, archived from the original on July 28, 2010 ; Retrieved July 1, 2013 .
  8. ↑ Gerold Stocker: Beaver (Castor fiber L.) in Switzerland . Federal Institute for Forest Research, August 1985. P. 12.
    Stocker refers to: Richard, PB, 1962: Détermination du sexe du castor vivant (Castor fiber).
  9. ↑ a b c d e f g h i j Rudolf Piechocki (1990): Elbebiber Castor fiber albicus Matschie. In: M. Stubbe (Ed.): Buch der Hege, Haarwild, pp. 588–615, ISBN 3-331-00169-4 .
  10. ↑ a b LUA Brandenburg (1999): Species protection program Elbe beaver and otter. 51 pp.
  11. ↑ Max Hoffmann: A contribution to the history of the spread of the beaver Castor fiber (Matschie 1907) in the large catchment area of ​​the Elbe
  12. ↑ Hinze, G. (1934): Our last German beavers. Dessau, quoted from: Dolch, D., Heidecke, D., Teubner, J. & Teubner, J. (2002): "Der Biber im Land Brandenburg", in: Naturschutz und Landschaftspflege in Brandenburg, 11, 4, p. 220-234.
  13. ↑ David Blackbourn : The Conquest of Nature. A history of the German landscape. Translated from the English by Udo Rennert. Pantheon, Munich 2008, ISBN 978-3-570-55063-2 , p. 141.
  14. ^ A b Dietrich Dolch, Dietrich Heidecke, Jana Teubner & Jens Teubner (2002): The beaver in the state of Brandenburg. - Nature Conservation And Landscape Management In Brandenburg 11 (4) 2002; 220-234.
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  16. ^ Adrian Campbell: 'First' sighting of wild beavers in England for centuries. February 27, 2014, accessed September 15, 2014 .
  17. ^ Forest management: Biber in Luxemburg. Luxembourg 2004 Online as PDF ( Memento from November 7, 2011 in the Internet Archive )
  18. ^ BUND Naturschutz: The current distribution of the beaver. Retrieved October 31, 2017 .
  19. ^ Beaver distribution and population in Germany - Manuscript for the beaver conference. Accessed June 27, 2011 (PDF file; 297 kB)
  20. ^ BUND Naturschutz: The current distribution of the beaver. Retrieved October 31, 2017 .
  21. ^ Südkurier Medienhaus: Baden-Württemberg: Will the beaver be hunted soon? | SÜDKURIER Online . In: SÜDKURIER Online . ( suedkurier.de [accessed on January 3, 2017]).
  22. ↑ Hessian Spessart beaver habitat (Jossa and Sinn) ( Memento from March 8, 2010 in the Internet Archive )
  23. ↑ Wild animals in Berlin-Spandau. Retrieved July 14, 2015
  24. ↑ "KB": Thuringia - new beaver advisors trained . www.antennethueringen.de, April 12, 2019. Last accessed on October 3, 2019.
  25. ↑ a b Federal Office for the Environment (Ed.): Concept Biber Switzerland . FOEN enforcement aid for beaver management in Switzerland. 2016 ( admin.ch [PDF; 1,2 MB ; accessed on December 26, 2019]).
  26. ↑ Report on www.news.admin.ch ( Memento from December 27, 2013 in the Internet Archive ), accessed on August 23, 2008
  27. ↑ Sieber, J. 2003. How many beavers are too many? Denisia 9: 3-11.
  28. ^ Slotta-Bachmayr, L. & H. Augustin. 2003. The beaver in the state of Salzburg. Denisia 9: 85-90.
  29. ↑ Sieber, J. 2003. How many beavers are too many? Denisia 9: 3-11.
  30. ↑ Parz-Gollner, R. & Vogl, W. 2006. Numbers, distribution and recent beaver conflicts in Austria. 4th European Beaver Symposium, 3rd Euro-American Beaver Congress, September 11-14, 2006, TU-Weihenstephan, Freising.
  31. ↑ Gerhard Schwab: Biology of the beaver. Seminar manuscript 2004 PDF file .
  32. ↑ Gerold Stocker: Beaver (Castor fiber L.) in Switzerland . Federal Institute for Forest Experiments, August 1985. P. 13.
    Stocker References: Djoshkin, WW, and Safonow, WG, 1972: The beavers of the old and new world .
  33. ↑ Volker Neumann: Red list of fur beetles . Red lists of Saxony-Anhalt, reports from the State Office for Environmental Protection Saxony-Anhalt, 2004.
  34. ↑ Stewart B. Peck: Distribution and biology of the ectoparasitic beaver beetle Platypsyllus castoris Ritsema in North America (Coleoptera: Leiodidae: Platypsyllinae) . Insecta Mundi 20 (1-2), March-June 2006. pp. 85-94.
  35. ↑ Mark Harthun: The influence of the beaver (Castor fiber albicus) on the fauna (Odonata, Mollusca, Trichoptera, Ephemeroptera, Diptera) of low mountain streams in Hesse (Germany). In: Limnologica - Ecology and Management of Inland Waters. 29 (4), 1999, pp. 449-464, doi : 10.1016 / S0075-9511 (99) 80052-8 .
  36. ↑ https://beaversinengland.com/beaver-biology/beavers-and-fish/ (accessed June 4, 2017)
  37. ↑ Lutz Dalbeck, Beatrice Lüscher & Dagmar Ohlhoff (2007): Beaver ponds as habitat of amphibian communities in a central European highland. Amphibia-Reptilia 28: 493-501.
  38. ^ Richard Pott (1996): Biotope Types. Ulmer, ISBN 3-8001-3484-5 , p. 150 f.
  39. ↑ Grzegorz Gabryś & Agnieszka Ważna: Subspecies of the European beaver Castor fiber Linnaeus, 1758. Acta Theriologica, Volume 48 (4), 2003; Pp. 433-439.
  40. ↑ Eurasian Beaver. In: Peter A. Busher: Family Castoridae (Beavers). In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (editors): Handbook of the Mammals of the World: Lagomorphs and Rodents 1. (HMW, Volume 6) Lynx Edicions, Barcelona 2016, p. 166- 167. ISBN 978-84-941892-3-4 .
  41. ↑ from: Hohberg, Wolf Helmhardt von, Georgica Curiosa Aucta, That is: Complicated report and clear teaching of the aristocratic country and field life, directed to all land and house management common in Germany, ... and in Zweyen peculiar parts , each of which is presented in six books ... In whose six books it is dealt with and described How to prepare the building grounds and fertile fields in the most useful and profitable way, as well as the studs, dressing and maintenance of the horses, as well as in the Mayerhöfe large and to raise small cattle ... Furthermore: How to order the meadow wax, to keep the bees and silkworms with good pleasure ...; Also to the decision are, book (Des Adelichen Land- und Feld-Lebens Eilfftes Buch / Wasser-Lust.), SLUB, Oecon.A.19-2
  42. ↑ Nitsche, K.-A. 2003. Beaver - Protection and Problems, Dessau.
  43. ^ Duncan Halley, Frank Rosell, Alexander Saveljev: Population and distribution of Eurasian beaver (Castor fiber) . In: Baltic Forestry . tape 18 , no. 1 , 2012, ISSN  2029-9230 , p. 168-175 ( researchgate.net [PDF]).
  44. ^ Christiane Frosch, Robert HS Kraus, Christof Angst, Rainer Allgöwer, Johan Michaux, Jana Teubner, Carsten Nowak: The Genetic Legacy of Multiple Beaver Reintroductions in Central Europe. In: PLOS ONE . tape 9 , no. 5 , 2014, p. 1 - 14 , doi : 10.1371 / journal.pone.0097619 .
  45. ^ Castor fiber at www.wisia.de
  46. ↑ BfN (2009): Red Lists of Endangered Animals, Plants and Fungi in Germany. Volume 1. Nature Conservation and Biodiversity Vol. 70 (1), 386 pp.
  47. ↑ Red Lists Switzerland: Mammals, accessed on June 28, 2011 (PDF file; 57 kB)