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Encyclopedia > Beaver
Beavers
Fossil range: Late Miocene – Recent
American Beaver
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Castoridae
Genus: Castor
Linnaeus, 1758
Species

C. canadensis
C. fiber
C. californicus Image File history File links Question_book-3. ... Beaver may refer to one of the following. ... The Miocene Epoch is a period of time that extends from about 23. ... Public domain picture from U.S. Fish and Wildlife Service File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Binomial name Castor canadensis Kuhl, 1820 A taxidermied American Beaver The American Beaver (Castor canadensis) is a large semi-aquatic rodent native to Canada, most of the United States and parts of northern Mexico. ... Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... For other uses, see Animal (disambiguation). ... Typical Classes See below Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates. ... Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the presence of sweat glands, including milk producing sweat glands, and by the presence of: hair, three middle ear bones used in hearing, and a neocortex... Suborders Sciuromorpha Castorimorpha Myomorpha Anomaluromorpha Hystricomorpha Rodentia 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. ... Genera †Eocastoroides †Steneofiber †Neatocastor †Asiacastor †Youngofiber †Trogontherium †Eucastor †Schreuderia †Dipoides †Boreofiber †Romanocastor †Zamolxifiber †Procastoroides †Castoroides †Paradipoides †Agnotocastor †Capacikala †Pseudopalaeocastor †Fossorcastor †Euhapsis †Propalaeocastor †Palaeomys †Palaeocastor †Hystricops Castor The family Castoridae contains the two living species of beaver and their fossil relatives. ... Carl Linnaeus, Latinized as Carolus Linnaeus, also known after his ennoblement as  , (May 13, 1707[1] – January 10, 1778), was a Swedish botanist, physician and zoologist[2] who laid the foundations for the modern scheme of nomenclature. ... For other uses, see Species (disambiguation). ... Binomial name Castor canadensis Kuhl, 1820 A taxidermied American Beaver The American Beaver (Castor canadensis) is a large semi-aquatic rodent native to Canada, most of the United States and parts of northern Mexico. ... Binomial name Castor fiber Linnaeus, 1758 Distribution of both species of beaver. ... Binomial name Synonyms †Castor accessor Hay, 1927[1] Kelloggs Beaver (Castor californicus) was a species of beaver that lived in western North America from the end of the Miocene to the early Pleistocene. ...

Beavers are semi-aquatic rodents native to North America and Europe. They are the only living members of the family Castoridae, which contains a single genus, Castor. Genetic research has shown the European and North American beaver populations to be distinct species and that hybridization is unlikely. Suborders Sciuromorpha Castorimorpha Myomorpha Anomaluromorpha Hystricomorpha Rodentia 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. ... North American redirects here. ... For other uses, see Europe (disambiguation). ... The hierarchy of scientific classification In biological classification, family (Latin: familia, plural familiae) is a rank, or a taxon in that rank. ... Genera †Eocastoroides †Steneofiber †Neatocastor †Asiacastor †Youngofiber †Trogontherium †Eucastor †Schreuderia †Dipoides †Boreofiber †Romanocastor †Zamolxifiber †Procastoroides †Castoroides †Paradipoides †Agnotocastor †Capacikala †Pseudopalaeocastor †Fossorcastor †Euhapsis †Propalaeocastor †Palaeomys †Palaeocastor †Hystricops Castor The family Castoridae contains the two living species of beaver and their fossil relatives. ... For other uses, see Genus (disambiguation). ... This article is about the general scientific term. ... This article is about the concept. ... For other uses, see Species (disambiguation). ... This article is about a biological term. ...

Contents

General

A beaver skull
A beaver skull

Beavers are best known for their natural trait of building dams in rivers and streams, and building their homes (known as beaver lodges) in the resulting pond. They are the second-largest rodent in the world (after the capybara). Image File history File links Biberschaedel-drawing. ... Image File history File links Biberschaedel-drawing. ... For other uses of Skull, see Skull (disambiguation). ... This article is about structures for water impoundment. ... For other uses, see River (disambiguation). ... Butchers Creek, Omeo, Victoria A stream, brook, beck, burn or creek, is a body of water with a detectable current, confined within a bed and banks. ... Two people reflected in a fish pond A pond is typically a man made body of water smaller than a lake. ... Binomial name (Linnaeus, 1766) Capybara range Capybara (Hydrochoerus hydrochaeris[1], known as carpincho in Spanish and capivara in Portuguese[2]) is the largest rodent still in existence in the world,[3] related to guinea pigs, agouti, coyphillas and chinchillas. ...


They are also known for their "danger signal": when startled or frightened, a swimming beaver will rapidly dive while forcefully slapping the water with its broad tail. This creates a loud 'slap', audible over large distances above and below water. This noise serves as a warning to other beavers in the area. Once a beaver has made this danger signal, all nearby beavers will dive and may not reemerge for some time.

Beaver tracks in snow, in Ontario. Hind paws approx. 20 cm long.
Beaver tracks in snow, in Ontario. Hind paws approx. 20 cm long.

Fossil remains of beavers are found in the peat and other superficial deposits of England and the continent of Europe; while in the Pleistocene formations of England and Siberia occur remains of a giant extinct beaver, Trogontherium cuvieri, representing a genus by itself. Image File history File links Beavertracks. ... Image File history File links Beavertracks. ... Motto: Ut Incepit Fidelis Sic Permanet (Latin: Loyal she began, loyal she remains) Capital Toronto Largest city Toronto Official languages English (de facto) Government Lieutenant-Governor David C. Onley Premier Dalton McGuinty (Liberal) Federal representation in Canadian Parliament House seats 107 Senate seats 24 Confederation July 1, 1867 (1st) Area... The Pleistocene epoch (IPA: ) on the geologic timescale is the period from 1,808,000 to 11,550 years BP. The Pleistocene epoch had been intended to cover the worlds recent period of repeated glaciations. ...


Beavers have webbed hind-feet, and a broad, scaly tail. They have poor eyesight, but a keen sense of hearing, smell, and touch.


Beavers continue to grow throughout life. Adult specimens weighing over 25 kg (55 lb) are not uncommon. Females are as large as or larger than males of the same age, which is uncommon among mammals. In biology, specimen is an individual animal or a plant or a microorganism that is used as a representative to study the properties of the whole population of that species. ... Kg redirects here. ... Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the presence of sweat glands, including milk producing sweat glands, and by the presence of: hair, three middle ear bones used in hearing, and a neocortex...


Etymology

The word is descended from the Proto-Indo-European name of the animal, cf. Sanskrit babhru's, brown, the great ichneumon, Lat. fiber, Ger. Biber, Swed. bäver, Russ. bobr'; the root bhru has given "brown," and, through Romanic, "bronze" and "burnish."[1] The Proto-Indo-European language (PIE) is the hypothetical common ancestor of the Indo-European languages, spoken by the Proto-Indo-Europeans. ...


Species

Beavers are closely related to squirrels (Sciuridae), agreeing in certain structural peculiarities of the lower jaw and skull. In the Sciuridae the two main bones (tibia and fibula) of the lower half of the leg are quite separate, the tail is round and hairy, and the habitats are arboreal and terrestrial. In the beavers or Castoridae these bones are in close contact at their lower ends, the tail is depressed, expanded and scaly, and their habitats are aquatic.[1] This article is about the animal. ...


Both European and American beavers grow to about 2 feet long (plus 10 inches of tail). They are essentially aquatic in their habits, never travelling by land unless driven by necessity. They are mainly nocturnal, and subsist chiefly on bark and twigs or the roots of water plants.


European Beaver

A European Beaver
A European Beaver

The European Beaver (Castor fiber) was hunted almost to extinction in Europe, both for fur and for castoreum, a secretion of its scent gland believed to have medicinal properties. However, the beaver is now being re-introduced throughout Europe. Several thousand live on the Elbe, the Rhone and in parts of Scandinavia. A thriving community lives in north east Poland, and the European Beaver also returned to the Morava River banks in Slovakia and the Czech Republic. They have been reintroduced in Bavaria, Austria, The Netherlands and Serbia (Zasavica bog) and are spreading to new locations. Image File history File links Beaver_pho34. ... Image File history File links Beaver_pho34. ... Binomial name Castor fiber Linnaeus, 1758 Distribution of both species of beaver. ... For other uses, see Extinction (disambiguation). ... Castoreum is the glandular secretion of the beaver. ... This article is about a river in Central Europe. ... Length 800 km Elevation of the source 1753 m Average discharge 1800 m³/ s Area watershed 100,200 km² Origin Rhône glacier Mouth Mediterranean Sea Basin countries Switzerland, France The River Rhône ( Latin Rhodanus, French Rhône, Occitan Rose, German Rotten) is one of the major rivers (ca. ... For other uses, see Scandinavia (disambiguation). ... There are several European rivers called Morava: Morava river, Central Europe Morava rivers, Serbia Morava is also the Czech and Slovak name for Moravia, the eastern part of the Czech Republic. ... Reintroduction is the deliberate release of animals from captivity into the wild. ... For other uses, see Bavaria (disambiguation). ... Motto: Je Maintiendrai (Dutch: Ik zal handhaven, English: I Shall Uphold) Anthem: Wilhelmus van Nassouwe Capital Amsterdam1 Largest city Amsterdam Official language(s) Dutch2 Government Parliamentary democracy Constitutional monarchy  - Queen Beatrix  - Prime minister Jan Peter Balkenende Independence Eighty Years War   - Declared July 26, 1581   - Recognised January 30, 1648 (by Spain... Not to be confused with Republika Srpska. ... The Zasavica (Serbian Cyrillic: Засавица) is a river, a bog and a village in the region of Mačva, western-central Serbia. ...


The beaver became extinct in Great Britain in the sixteenth century: Giraldus Cambrensis reported in 1188 (Itinerarium ii.iii) that it was to be found only in the Teifi in Wales and in one river in Scotland, though his observations are clearly first hand. In October 2005, six European beavers were re-introduced to Britain in Lower Mill Estate in Gloucestershire; in July of 2007 a colony of four European beavers was established at Martin Mere in Lancashire,[2] and there are plans for re-introductions in Scotland and Wales.[3][4] (15th century - 16th century - 17th century - more centuries) As a means of recording the passage of time, the 16th century was that century which lasted from 1501 to 1600. ... Giraldus Cambrensis (c. ... The River Teifi (Welsh: Afon Teifi) is a river in West Wales flowing into the sea below Cardigan town. ... This article is about the country. ... This article is about the country. ... First hand is where one experiences something personally, in effect, within reach of ones hands, also known as first person. ... Gloucestershire (pronounced ; GLOSS-ter-sher) is a county in South West England. ... It has been suggested that this article or section be merged with WWT Martin Mere. ... Lancashire is a non-metropolitan county of historic origin in the North West of England, bounded to the west by the Irish Sea. ...


American Beaver

An American Beaver
An American Beaver

The American Beaver (Castor canadensis), also called Canadian Beaver (which is also the name of a subspecies), or simply Beaver in North America, is native to Canada, much of the United States and parts of northern Mexico. The chief feature distinguishing C. canadensis from C. fiber is the form of the nasal bones of the skull.[1] This species was introduced to the Argentine and Chilean Tierra del Fuego, as well as Finland, France, Poland and Russia. Image File history File links Download high-resolution version (1000x750, 368 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): American Beaver List of North American mammals List of Massachusetts mammals Mammals of New England ... Image File history File links Download high-resolution version (1000x750, 368 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): American Beaver List of North American mammals List of Massachusetts mammals Mammals of New England ... Binomial name Castor canadensis Kuhl, 1820 A taxidermied American Beaver The American Beaver (Castor canadensis) is a large semi-aquatic rodent native to Canada, most of the United States and parts of northern Mexico. ...


The American beaver's preferred food[citation needed]is the water-lily (Nuphar luteum), which bears a resemblance to a cabbage-stalk, and grows at the bottom of lakes and rivers. Beavers also gnaw the bark of birch, poplar and willow trees; but during the summer a more varied herbage, with the addition of berries, is consumed. Binomial name Nuphar lutea L. Sm. ... Percentages are relative to US recommendations for adults. ... This article is about woody plants of the genus Populus. ...


These animals are often trapped for their fur. During the early 19th century, trapping eliminated this animal from large portions of its original range. However, through trap and transfer and habitat conservation it made a nearly complete recovery by the 1940s. Beaver furs were used to make clothing and top-hats. Much of the early exploration of North America was driven by the quest for this animal's fur. Native peoples and early settlers also ate this animal's meat. The current beaver population has been estimated to be 10 to 15 million; one estimate claims that there may at one time have been as many as 90 million[5]


Giant beaver

The North American Giant beaver (Castoroides ohioensis) was one of largest rodents that ever evolved. It disappeared along with other large mammals in the Holocene extinction event, which began about 13,000 years ago. Since then it has not changed much in the evolution cycle. Binomial name Castoroides ohioensis The Giant Beaver (Castoroides ohioensis) was a huge species of rodent, with a length up to 2. ... This article is about evolution in biology. ... The Dodo, a bird of Mauritius, became extinct during the mid-late 17th century after humans destroyed the forests where the birds made their homes and introduced animals that ate their eggs. ...


Habitat

The habitat of the beaver is the riparian zone inclusive of stream bed. The actions of beavers for hundreds of thousands of years in the Northern Hemisphere have kept these watery systems healthy and in good repair, although a human observing all the downed trees might think that the beavers were doing just the opposite. A well preserved Riparian strip on a tributary to Lake Erie. ... Northern hemisphere highlighted in yellow. ...


The beaver works as a keystone species in an ecosystem by creating wetlands that are used by many other species. Next to humans, no other extant animal appears to do more to shape its landscape[citation needed]. This article or section does not cite its references or sources. ... For other uses, see Ecological Systems Theory. ... A subtropical wetland in Florida, USA, with an endangered American Crocodile. ...


The Dam's Primary Role: The Beaver's Home

Beaver dams are created both as a protection against predators, such as coyotes, wolves and bears, and to provide easy access to food during winter. Beavers always work at night and are prolific builders, carrying mud and stones with their fore-paws and timber between their teeth. Because of this, destroying a beaver dam without removing the beavers is difficult, especially if the dam is downstream of an active lodge. Beavers can rebuild such primary dams overnight, though they may not defend secondary dams as vigorously. For other uses, see Coyote (disambiguation). ... Wolf Wolf Man Mount Wolf Wolf Prizes Wolf Spider Wolf 424 Wolf 359 Wolf Point Wolf-herring Frank Wolf Friedrich Wolf Friedrich August Wolf Hugo Wolf Johannes Wolf Julius Wolf Max Franz Joseph Cornelius Wolf Maximilian Wolf Rudolf Wolf Thomas Wolf As Name Wolf Breidenbach Wolf Hirshorn Other The call... For other uses, see Bear (disambiguation). ...


Shape of dam

A dam's shape depends on the strength of the stream's current. Relatively still water encourages dams that are almost straight; while dams in stronger currents are curved, with the convexity pointing upstream. The beavers use driftwood, green willows, birch and poplars; and they mix in mud and stones in ways that contribute to the dam's strength. Image File history File linksMetadata BeaverDam_8409. ... Image File history File linksMetadata BeaverDam_8409. ... Map of Lassen area showing hydrothermal features (red dots) and volcanic feature or remnant (yellow cones). ... A piece of waterlogged driftwood Driftwood is wood that has been washed onto a shore or beach by the action of the waves. ... Species Many species; see text and classification Birch is the name of any tree of the genus Betula, in the family Betulaceae, closely related to the beech/oak family, Fagaceae. ...


Beavers have been known to build very large dams.[6] The largest known was discovered by satellite imagery in Northern Alberta in 2007, approximately 850 meters (2790 feet) long [7], beating the previous record holder found near Three Forks, Montana, at 2,140 feet long, 14 feet high, and 23 feet thick at the base.[8] When objectionable beaver flooding occurs, modern water level control devices can be installed for a cost-effective and environmentally sound solution. Unwanted damage to trees can be prevented by wrapping chicken wire or sheet metal around the base of trees.[9]

Canoeists try unsuccessfully to run a beaver dam in Algonquin Park. The dam is about 1 m high.

"In places," writes Hearne, "which have been long frequented by beavers undisturbed, their dams, by frequent repairing, become a solid bank, capable of resisting a great force both of ice and water; and as the willow, poplar and birch generally take root and shoot up, they by degrees form a kind of regular planted hedge, which I have seen in some places so tall that birds have built their nests among the branches."[citation needed] Image File history File linksMetadata Download high-resolution version (1200x1600, 1552 KB) Picture taken by me, in Algonquin Park, unsuccesfully trying to run a beaver dam. ... Image File history File linksMetadata Download high-resolution version (1200x1600, 1552 KB) Picture taken by me, in Algonquin Park, unsuccesfully trying to run a beaver dam. ... Algonquin Provincial Park is a Provincial Park in central Ontario, Canada. ...


Stimulus for dam-building

It is primarily prolonged exposure to the sound of water in motion that stimulates the beavers to build. However, studies involving beaver habitual activities have indicated that beavers may respond to an array of stimuli, not just the sound of running water. In two experiments Wilson (1971) and Richard (1967, 1980) demonstrate that, although beavers will pile material close to a loudspeaker emitting sounds of water running,[10] they only do so after a considerable period of time. Additionally the beavers, when faced with a pipe allowing water to pass through their dam, eventually stopped the flow of water by plugging the pipe with mud and sticks. The beavers were observed to do this even when the pipe extended several meters upstream and near the bottom of the stream and thus produced no sound of running water. Beavers normally repair damage to the dam and build it higher as long as the sound continues. However, in times of high water, they often allow spillways in the dam to flow freely.


Disruption by dams

Trees, up to 250 mm (10 inches) in diameter, felled by beavers in one night.
Trees, up to 250 mm (10 inches) in diameter, felled by beavers in one night.
A tree abandoned by beavers, presumably too large
A tree abandoned by beavers, presumably too large

Beaver dams can be disruptive; the flooding can cause extensive property damage, and when the flooding occurs next to a railroad roadbed, it can cause derailments by washing-out under the tracks, or when a beaver dam bursts and the resulting flash flood overwhelms a culvert. This disruption is not limited to human geography; beavers can destroy nesting habitat for endangered species, and often destroy mature trees for which they have no use. Introduced to an area without its natural predators, as in Tierra del Fuego, beavers have flooded thousands of acres of land and are considered an unstoppable plague. One notable difference in Tierra del Fuego from most of North America is that the trees found in Tierra del Fuego do not coppice as do willows, poplars, aspens, and other North American trees. Thus the "damage" by the beavers seems more severe. Image File history File links Download high resolution version (1280x960, 589 KB) Summary Evidence of trees eaten by Beavers in Boyer Chute National Wildlife Refuge Photo taken by MONGO 11-11-05 Licensing File links The following pages link to this file: Beaver Talk:Beaver User:MONGO Boyer Chute National... Image File history File links Download high resolution version (1280x960, 589 KB) Summary Evidence of trees eaten by Beavers in Boyer Chute National Wildlife Refuge Photo taken by MONGO 11-11-05 Licensing File links The following pages link to this file: Beaver Talk:Beaver User:MONGO Boyer Chute National... Image File history File linksMetadata Size of this preview: 450 × 600 pixelsFull resolution (1200 × 1600 pixel, file size: 245 KB, MIME type: image/jpeg) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File linksMetadata Size of this preview: 450 × 600 pixelsFull resolution (1200 × 1600 pixel, file size: 245 KB, MIME type: image/jpeg) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Download high resolution version (2048x1536, 1090 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (2048x1536, 1090 KB) Wikipedia does not have an article with this exact name. ... Tierra del Fuego Cerro Sombrero Village, Chile. ... Tierra del Fuego Cerro Sombrero Village, Chile. ... A recently coppiced Alder stool in Hampshire Coppicing is a traditional method of woodland management, by which young tree stems are cut down to a low level, or sometimes right down to the ground. ...


Benefits of dams compared to disruption

On the other hand, dam building is extremely beneficial in restoring wetlands. Such wetland benefits include flood control downstream, biodiversity (by providing habitat for many rare as well as common species), and water cleansing, both by the breakdown of toxins such as pesticides and the retention of silt by beaver dams. Over the eons, this collection of silt produces the rich bottom land so sought after by farmers. Beaver dams also reduce erosion as well as decrease the turbidity that is a limiting factor for much aquatic life. While beavers can create damage, part of the problem is one of perception and time scale. Such damage as the undermining of a roadway or the drowning of some trees is very visible shortly after the beginning of beavers' activity in an area. The benefits, mentioned below, are long-term and not easily seen except by someone who is monitoring a catchment and realizes the beneficial effects of beaver dams.


The Dam's Role in the Stream's Lifecycle

Drained beaver dam in Allegany State Park.
Drained beaver dam in Allegany State Park.

Image File history File linksMetadata Download high-resolution version (3264x2448, 2813 KB) Summary A beaver dam in Allegheny State Park NY which has burst and been drained of its water. ... Image File history File linksMetadata Download high-resolution version (3264x2448, 2813 KB) Summary A beaver dam in Allegheny State Park NY which has burst and been drained of its water. ... The Administration Building from across Red House Lake Allegany State Park is a state park in western New York State, located in Cattaraugus County, just north of Allegheny National Forest in Pennsylvania. ...

Wetland creation

If a beaver pond becomes too shallow due to the settling of sediment, or if the tree supply is depleted, beavers will abandon the site. Eventually the dam will be breached and the water will drain out. The rich thick layer of silt, branches, and dead leaves behind the old dam is the ideal habitat for wetland species. Many of them will have been on the fringes of the pond. Wetlands have significant environmental benefits. A subtropical wetland in Florida, USA, with an endangered American Crocodile. ...


The grazing meadow (vega)

As the wetland fills and dries out, pasture species colonize it and it becomes a meadow suitable for grazing. In an area with nothing but forest down to the stream edge, this provides a valuable niche for many animals which otherwise would be excluded.


The riverine forest

Finally the meadow will be colonized by riverine trees, typically aspens, willows and such species which are favoured by the beaver. Beavers are then likely to recolonize the area, and the cycle begins again.


The Dam's Beneficial Effects in the Ecology

Bottom land

Each time the stream lifecycle repeats itself another layer of rich organic soil is added to the bottom of the valley. The valley slowly fills and the flat area at the bottom gets wider. Research is sparse on this topic, but it seems likely that much of the fabled bottom land in North America was created, or at least added to, by the efforts of the generations of beavers that lived there.


Flood control

A beaver dam has a certain amount of freeboard above the water level. When heavy rains occur, the pond fills up and the dam gradually releases the extra stored water. Often this is all that is necessary to reduce the height of the flood wave moving down the river, and will reduce or eliminate damage to human structures. Flood control is achieved in other ways as well. The surface of any stream intersects the surrounding water table. By raising the stream level, the gradient of the surface of the water table above the beaver dam is reduced, and water near the beaver dam flows more slowly into the stream. This further helps in reducing flood waves, and increases water flow when there is no rain. Beaver dams also smooth out water flow by increasing the area wetted by the stream. This allows more water to seep into the ground where its flow is slowed. This water eventually finds its way back to the stream. Rivers with beaver dams in their head waters have lower high water and higher low water levels. Freebord model X-80, bottom side Freebords are a recent modification of the skateboard. ...


Nutrient removal

The removal of nutrients from the stream flow by beaver ponds is an interesting and very valuable process. Farming along the banks of rivers often increases the loads of phosphates, nitrates and other nutrients, causing problems downstream when this water is extracted for drinking. Besides silt, the beaver dam collects twigs and branches from the beavers' activity and leaves, notably in the fall. The main component of this material is cellulose, a polymer of β-glucose monomers (This creates a more crystalline structure than is found in starch, which is composed of α-glucose monomers. Cellulose is a type of polysaccharide.) Many bacteria produce cellulase which can split off the glucose and use it for energy. Just as algae get their energy from sunlight, these bacteria get their energy from cellulose, and they form the base of a very similar food chain. However, a source of energy is not enough for growth. These bacterial populations face serious shortages of nitrous and phosporous compounds, and will absorb these nutrients as they pass by in the water stream. In this way, these and other nutrients are fixed into the beaver pond and the surrounding ecology, and are removed from the stream. Cellulose as polymer of β-D-glucose Cellulose in 3D Cellulose (C6H10O5)n is a polysaccharide of beta-glucose. ... A polymer (from Greek: πολυ, polu, many; and μέρος, meros, part) is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. ... In chemistry, a monomer (from Greek mono one and meros part) is a small molecule that may become chemically bonded to other monomers to form a polymer. ... Starch (CAS# 9005-25-8, chemical formula (C6H10O5)n,[1]) is a mixture of amylose and amylopectin (usually in 20:80 or 30:70 ratios). ... Polysaccharides (sometimes called glycans) are relatively complex carbohydrates. ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ...


Pesticide and herbicide removal

Agriculture also introduces herbicides and pesticides into our streams. Bacteria are an extremely variable lot and some of these toxicants are metabolized and decomposed by the bacteria in the cellulose-rich bottom of a beaver dam. A toxicant is a chemical compound that has an effect on organisms. ...


Denitrification

Some scientists believe that the nitrate cascade, the production of far more fixed nitrogen than the natural cycles can turn back into nitrogen gas, may be as much of a problem to our ecology as carbon dioxide production. It is likely, but not proven, that beaver dams along a stream may contribute to denitrification (the conversion of nitrogen compounds back into nitrogen). In sewage plants, denitrification is achieved by passing the water through successive aerobic and anaerobic stages. Under a beaver dam, as the water seeps down into the soil, the oxygen is consumed by the fauna in the rich organic layer. At some point all the oxygen is used up and the soil becomes anaerobic. This water eventually finds its way back into the aerobic stream and into another beaver dam. This aerobic, anaerobic cycle continues all the way down the stream and denitrification is a likely result. This does not cite its references or sources. ...


Beaver and Salmon

Beaver dams are a nursery for salmon. An early indication of this was seen following the 1818 agreement between the British government of Canada and the government of America allowing Americans access to the Columbia watershed. The Hudson's Bay Company, in a fit of pique sent word to its trappers to extirpate the fur bearing animals in the area. The beaver was the first to go. Salmon runs fell precipitously in the following years even though, at that time, none of the factors were extant that we associate with the decline of salmon runs.[11]


The functions of beaver dams in increasing salmon runs are many. They provide deep enough water for the juvenile salmon to hide from predatory wading birds. They trap nutrients in their ecology and notably the huge nutrient pulse represented by the migration of the adult salmon upstream. These nutrients help feed the juveniles after they finish their yoke. They provide quiet water so that the young salmon can put energy into growth rather than into fighting currents and larger smolt with a food reserve have a better chance when they reach the sea. And beaver dams keep the water clear which favours all the salmonoids, trout included.


Lodges

Beaver lodge, approx. 20-foot diameter. Ontario, Canada
Beaver lodge, approx. 20-foot diameter. Ontario, Canada

The ponds created by well-maintained dams help isolate the beavers' home, their lodge, which is also created from severed branches and mud. The beavers cover their lodges late every autumn with fresh mud which freezes when the frost sets in. The mud becomes almost as hard as stone, so that neither wolves nor wolverines can get in. Image File history File links Download high resolution version (842x566, 111 KB) Summary Beaver Lodge, 15 Apr 2006. ... Image File history File links Download high resolution version (842x566, 111 KB) Summary Beaver Lodge, 15 Apr 2006. ... Motto: Ut Incepit Fidelis Sic Permanet (Loyal she began, loyal she remains) Other Canadian provinces and territories Capital Toronto Largest city Toronto Lieutenant Governor James K. Bartleman Premier Dalton McGuinty (Liberal) Area 1,076,395 km² (4th)  - Land 917,741 km²  - Water 158,654 km² (14. ... For other uses, see Wolverine (disambiguation). ...


The lodge has underwater entrances to make entry nearly impossible for any other animal (however, muskrats have been seen living inside beaver lodges with the beavers who made it). A very small amount of the lodge is actually used as a living area. Contrary to popular belief, beavers actually dig out their den with an underwater entrance after they finish building the dam and lodge structure. There are typically two dens within the lodge, one for drying off after exiting the water, and another, drier one where the family actually lives. Binomial name Ondatra zibethicus (Linnaeus, 1766) The Muskrat or Musquash (Ondatra zibethicus), the only species in genus Ondatra, is a large aquatic rodent native to North America, and introduced in parts of Europe. ...


Their houses are formed of the same materials as the dams, with little order or regularity of structure, and seldom contain more than four old, and six or eight young beavers. Sometimes some of the larger houses have one or more partitions, but these are only posts of the main building left by the builders to support the roof, for the apartments have usually no communication with each other except by water.


When the ice breaks up in spring they always leave their embankments, and rove about until a little before fall, when they return to their old habitations, and lay in their winter stock of wood. They seldom begin to repair the houses till the frost sets in, and never finish the outer coating till the cold becomes severe. When they erect a new habitation they fell the wood early in summer, but seldom begin building till towards the end of August.


Invasiveness

Beavers can create serious damage when spread outside of their natural environment, and are therefore considered in some places as pests or invasive species. For example, in the 1940s, beavers were brought to the island of Tierra Del Fuego in southern Argentina, for commercial fur production. However, the project failed and the beavers were released into the wild. Having no natural predators in their new environment, they quickly spread throughout the island, reaching a number of 100,000 individuals within just 50 years (when released into the wild there were only a few pairs). They are now considered a serious invasive species on the island, due to their massive destruction of forest trees, and efforts are being made for their eradication.[12] Lantana invasion of abandoned citrus plantation; Moshav Sdey Hemed, Israel The term invasive species refers to a subset of introduced species or non-indigenous species that are rapidly expanding outside of their native range. ... Tierra del Fuego Cerro Sombrero Village, Chile. ...


Commercial Uses

Beaver pelts were used for barter by Native Americans in the 17th century to gain European goods. They were then shipped back to Great Britain and France where they were made into clothing items. Widespread hunting and trapping of beavers led to their endangerment. Eventually, the fur trade fell apart due to declining demand in Europe and the takeover of trapping grounds to support the growing agriculture sector. A small resurgence in beaver trapping has occurred in some areas where there is an over-population of beaver; trapping is only done when the fur is of value, and normally the remainder of the animal is also utilized as animal feed. The only fur in North America which surpassed the beaver's in commercial value was that of the silver morph red fox, which was said to be forty times more valuable.[13] Barter is a type of trade that do not use any medium of exchange, in which goods or services are exchanged for other goods and/or services. ... For other uses, see Native Americans (disambiguation). ... (16th century - 17th century - 18th century - more centuries) As a means of recording the passage of time, the 17th century was that century which lasted from 1601-1700. ... An Alberta fur trader in the 1890s. ... For other uses, see Red Fox (disambiguation). ...


Both beaver testicles and castoreum, a bitter-tasting secretion with a slightly fetid odor contained in dried preputial or vaginal follicles of male or female beaver, have been articles of trade for use in traditional medicine. Yupik (Eskimo) medicine used dried beaver testicles like willow bark to relieve pain.[14] Beaver testicles were exported from Levant (a region centered on Israel) from the tenth to nineteenth century.[15] Claudius Aelianus comically described beavers chewing off their testicles to preserve themselves from hunters.[16] European beavers (Castor fiber) were eventually hunted nearly to extinction in part for the production of castoreum, which as used as an analgesic, anti-inflammatory, and antipyretic. Castoreum was described in the 1911 British Pharmaceutical Codex for use in dysmenorrhea and hysterical conditions (i.e. pertaining to the womb), for raising blood pressure and increasing cardiac output. The activity of castoreum has been credited to the accumulation of salicin from willow trees in the beaver's diet, which is transformed to salicylic acid and has an action very similar to aspirin.[17] Castoreum continues to be used in perfume production. Castoreum is the glandular secretion of the beaver. ... This article is about Yupik peoples in general. ... For other uses, see Eskimo (disambiguation). ... The Levant The Levant (IPA: ) is an imprecise geographical term historically referring to a large area in the Middle East south of the Taurus Mountains, bounded by the Mediterranean Sea on the west, and by the northern Arabian Desert and Upper Mesopotamia to the east. ... Claudius Aelianus (c. ... Binomial name Linnaeus, 1758 Image:Leefgebied bever. ... An analgesic (colloquially known as a painkiller) is any member of the diverse group of drugs used to relieve pain (achieve analgesia). ... Anti-inflammatory refers to the property of a substance or treatment that reduces inflammation. ... Antipyretics are drugs that prevent or reduce fever by lowering the body temperature from a raised state. ... This article or section does not cite any references or sources. ... Dysmenorrhea (or dysmenorrhoea) is a medical condition characterized by severe uterine pain during menstruation. ... For the album, see Hysteria (album) Professor Jean-Martin Charcot was well-known for showing, during his lessons at the Salpêtrière hospital, hysterical woman patients – here, his favorite patient, Blanche (Marie) Wittman, supported by Joseph Babinsky. ... A sphygmomanometer, a device used for measuring arterial pressure. ... Cardiac output (CO) is the volume of blood being pumped by the heart, in particular by a ventricle in a minute. ... Salicylic acid is a colorless, crystalline organic carboxylic acid. ... Species About 350, including: Salix acutifolia - Violet Willow Salix alaxensis - Alaska Willow Salix alba - White Willow Salix alpina - Alpine Willow Salix amygdaloides - Peachleaf Willow Salix arbuscula - Mountain Willow Salix arbusculoides - Littletree Willow Salix arctica - Arctic Willow Salix atrocinerea Salix aurita - Eared Willow Salix babylonica - Peking Willow Salix bakko Salix barrattiana... Salicylic acid (from the Latin word for the willow tree, Salix, from whose bark it can be obtained) is a beta hydroxy acid (BHA) with the formula C6H4(OH)CO2H, where the OH group is adjacent to the carboxyl group. ... This article is about the drug. ... For other uses, see Perfume (disambiguation). ...


Beavers in culture

A Beaver on the Canadian 5 Cent Coin (Nickel)
Mrs and Mr Beaver in The Chronicles of Narnia: The Lion, the Witch and the Wardrobe.

Image File history File links Size of this preview: 615 × 599 pixel Image in higher resolution (1010 × 984 pixel, file size: 116 KB, MIME type: image/jpeg) Depiction of a North American Beaver on the Canadian 5 Cent coin. ... Image File history File links Size of this preview: 615 × 599 pixel Image in higher resolution (1010 × 984 pixel, file size: 116 KB, MIME type: image/jpeg) Depiction of a North American Beaver on the Canadian 5 Cent coin. ...

Characters in media

Look up Fantasy in Wiktionary, the free dictionary For other definitions of fantasy, see fantasy (psychology). ... This article is about the novel. ... The Tent Dwellers, 1985 Nimbus Publishing cover The Tent Dwellers is a book by Albert Bigelow Paine, chronicling his travels through inland Nova Scotia on a trout fishing trip with Dr. Edward Eddie Breck, and with guides Charles the Strong and Del the Stout, one June in the early 1900s. ... Albert Bigelow Paine (10 July 1861 – 9 April 1937) was an American author and biographer best known for his work with Mark Twain. ... This article is about the TV channel. ... The Angry Beavers is an Emmy Award nominated Nickelodeon American animated television series about Daggett and Norbert Beaver, two brothers who are beavers who have left their parents and home to become bachelors in the forest. ... Toothy is a fictional character in the cartoon series Happy Tree Friends. ... Look up handy in Wiktionary, the free dictionary. ... Happy Tree Friends is a Flash cartoon series by Mondo Mini Shows, created by Kenn Navarro, Aubrey Ankrum, Rhode Montijo and Warren Graff. ... Dougal Dixon (born 1947) is a Scottish geologist. ... John Cleese (right) and Michael Palin (left) of Monty Python performing the Cheese Shop sketch. ... This article is about the television series. ... The official Pokémon logo. ... Bibarel , Beadull in original Japanese language versions) are one of the 493 fictional species of Pokémon creatures from the multi-billion-dollar[1] Pokémon media franchise – a collection of video games, anime, manga, books, trading cards and other media, created by Satoshi Tajiri. ...

Mascots, political and other

An Alberta fur trader in the 1890s. ... This is a list of national animals: // Main article: List of U.S. state amphibians Main article: List of U.S. state birds Main article: List of U.S. state butterflies Main article: List of U.S. state dinosaurs Main article: List of U.S. state fish Main article: List... A Canadian nickel is a coin worth five cents, patterned on the corresponding coin in the neighbouring United States, and introduced in Canada in 1922. ... A selection of Hong Kong postage stamps A postage stamp is evidence of pre-paying a fee for postal services. ... British North America consisted of the loyalist colonies and territories (i. ... The postal history of Canada falls into four major periods: French control (1608-1763), British control (1763-1851), provincial control (1851-1868), and the Dominion of Canada, since 1868. ... A national symbol is a symbol of any entity considering itself and manifesting itself to the world as a national community – namely sovereign states, but also nations and countries in a state of colonial or other dependence, (con)federal integration, or even an ethnocultural community considered a nationality despite the... Millie, once mascot of the City of Brampton, is now the Brampton Arts Councils representative. ... The 1976 Summer Olympics, officially known as the Games of the XXI Olympiad, were held in 1976 in Montreal, Quebec, Canada. ... Nickname: Motto: Concordia Salus (well-being through harmony) Coordinates: , Country Province Region Montréal Founded 1642 Established 1832 Government  - Mayor Gérald Tremblay Area [1][2][3]  - City 365. ... Algonquin (or Algonkin) is an Algonquian language closely related to Ojibwe. ... The Canadian Forces (CF) (French: Forces canadiennes (FC)) are the unified armed forces of Canada, governed by the National Defence Act, which states: The Canadian Forces are the armed forces of Her Majesty raised by Canada and consist of one Service called the Canadian Armed Forces. ... Badge of Le Royal 22e Régiment The Royal 22e Régiment is an infantry regiment and the most famous francophone organization of the Canadian Forces. ... Canadian Military Engineers // Canadian Military Engineers History Creation Following the Boer War the Canadian Government realized that more the defence of Canada required more than just a single infantry battalion and a few artillery batteries as part of the permament defence force. ... This article is about the U.S. state. ... Computer-generated imagery[1] (also known as CGI) is the application of the field of computer graphics or, more specifically, 3D computer graphics to special effects in films, television programs, commercials, simulators and simulation generally, and printed media. ... Bell Canada Enterprises (TSX: BCE, NYSE: BCE), legally BCE Inc. ... A state mammal is the official or representative animal of a U.S. state. ... This article is about the state. ... New Netherland (Dutch Nieuw-Nederland, Latin: Nova Belgica) was the territory claimed by the Netherlands on the eastern coast of North America in the 17th century. ... New York, New York and NYC redirect here. ... A modern coat of arms is derived from the medi val practice of painting designs onto the shield and outer clothing of knights to enable them to be identified in battle, and later in tournaments. ... “MIT” redirects here. ... The California Institute of Technology (commonly referred to as Caltech)[1] is a private, coeducational research university located in Pasadena, California, in the United States. ... The City College of The City University of New York (known more commonly as City College of New York or simply City College, CCNY, or colloquially as City) is a senior college of the City University of New York, in New York City. ... Oregon State University (OSU) is a coeducational, public research university located in Corvallis, Oregon, United States. ... The University of Toronto (U of T) is a public research university in the city of Toronto, Ontario, Canada. ... Mascot: Beaver Affiliations: University of London Russell Group EUA ACU CEMS APSIA Universities UK U8 Golden Triangle G5 Group Website: http://www. ...

Organizations

An American Beaver in Calgary, Alberta
An American Beaver in Calgary, Alberta
  • Canadian children between 5 and 7 can join "Beavers", the youngest organization in the Scouts Canada movement. During meetings, children gather at the "pond", which is the site of their "colony". Within the colony, the children are divided into "lodges".[18]

For the Boy Scouting program within the BSA, see Boy Scouting (Boy Scouts of America). ... Wood Badge is a Scouting leadership program and the related award for adult leaders in the programs of Scout associations around the world. ... Image File history File links Size of this preview: 800 × 532 pixel Image in higher resolution (1000 × 665 pixel, file size: 72 KB, MIME type: image/jpeg) North American Beaver at Carburn Park in Calgary, Alberta. ... Image File history File links Size of this preview: 800 × 532 pixel Image in higher resolution (1000 × 665 pixel, file size: 72 KB, MIME type: image/jpeg) North American Beaver at Carburn Park in Calgary, Alberta. ... This article is about the Canadian city. ... For other uses, see Alberta (disambiguation). ...

Miscellaneous

  • In the 17th century, based on a question raised by the Bishop of Quebec, the Roman Catholic Church ruled that the beaver was a fish for purposes of dietary law. Therefore, the general prohibition on the consumption of meat on Fridays during Lent does not apply to beaver meat.[19][20][21] The legal basis for the decision probably rests with the Summa Theologica of Thomas Aquinas, which bases animal classification as much on habit as anatomy.[22]
  • In computability theory, a Busy Beaver is a Turing machine which does as much work as possible given the size of its tape alphabet and underlying state machine.
  • Someone with large frontal teeth (or 'buckteeth') can be referred to as a beaver.
  • Beaver also represents vagina in slang.[citation needed]

Topics in Christianity Movements · Denominations · Other religions Ecumenism · Preaching · Prayer Music · Liturgy · Calendar Symbols · Art · Criticism Important figures Apostle Paul · Church Fathers Constantine · Athanasius · Augustine Anselm · Aquinas · Palamas · Luther Calvin · Wesley Arius · Marcion of Sinope Archbishop of Canterbury · Catholic Pope Coptic Pope · Ecumenical Patriarch Christianity Portal This box:      This article... This article is about the Canadian province. ... Catholic Church redirects here. ... For other uses, see Fish (disambiguation). ... For other uses, see Meat (disambiguation). ... For other uses, see Lent (disambiguation). ... Summa theologiae, Pars secunda, prima pars. ... Aquinas redirects here. ... Computability theory is the branch of theoretical computer science that studies which problems are computationally solvable using different models of computation. ... In computability theory, a Busy Beaver (from the colloquial expression for industrious person) is a Turing machine that, when given an empty tape, does a lot of work, then halts. ... For the test of artificial intelligence, see Turing test. ... The vagina, (from Latin, literally sheath or scabbard ) is the tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. ... For other uses, see Slang (disambiguation). ...

References

  1. ^ a b c Encyclopedia Brittanica 11th Edn
  2. ^ "Beavers are back after 500 years", BBC News, 2007-7-11. 
  3. ^ Return of the Beavers at MSN.co.uk
  4. ^ Beavers could be released in 2009. BBC (2007-12-24).
  5. ^ Seton-Thompson, cited in Sun, Lixing; Dietland Müller-Schwarze (2003). The Beaver: Natural History of a Wetlands Engineer. Cornell University Press. ISBN 080144098X.  pp97-98; but note that to arrive at this figure he assumed a population density throughout the range equivalent to that in Algonquin Park
  6. ^ Big Beaver Dam on Grand Island, Lake Superior
  7. ^ [1]
  8. ^ beaver.html
  9. ^ Beavers: Wetlands & Wildlife
  10. ^ 'Why Beavers Build Dams' at Natural Events Almanac
  11. ^ 'Beavers' at The Northwest Power and Conservation Council
  12. ^ CNN - Argentina eager to rid island of beavers - July 9, 1999
  13. ^ Morton, Thomas (1972). New English Canaan: Or, New Canaan (Research Library of Colonial Americana), pp.188. ISBN 0405033095. 
  14. ^ Yupik Eskimo home remedies. Retrieved on 2007-06-17.
  15. ^ PMID 12576209
  16. ^ Claudius Aelianus: Beaver Testicles and Red-Hot Feline Semen.
  17. ^ Stephen Pincock (2005-03-28). The quest for pain relief: how much have we improved on the past?. Retrieved on 2007-06-17.
  18. ^ scouts.ca
  19. ^ http://www.chowdc.org/Papers/Saunders%202001.html
  20. ^ JIMMY AKIN.ORG: Lenten Reader Roundup
  21. ^ (French)Lacoursière, Jacques. Une histoire du Québec ISBN 2-89448-050-4 Explains that Bishop François de Laval in the 17th century posed the question to the theologians of the Sorbonne, who ruled in favour of this decision.
  22. ^ The Summa Theologica of St. Thomas Aquinas II. 147:8 provides legal foundation upon which theologians argued in favour of beaver being like fish.
  • ITIS 180211 2002-12-14

This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain. BBC News is the department within the BBC responsible for the corporations news-gathering and production of news programmes on BBC television, radio and online. ... For other uses, see MSN (disambiguation). ... For other uses, see BBC (disambiguation). ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 358th day of the year (359th in leap years) in the Gregorian calendar. ... Algonquin Provincial Park is a Provincial Park in central Ontario, Canada. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 168th day of the year (169th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 87th day of the year (88th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 168th day of the year (169th in leap years) in the Gregorian calendar. ... Inscription over the entrance to the Sorbonne The front of the Sorbonne Building The name Sorbonne (La Sorbonne) is commonly used to refer to the historic University of Paris in Paris, France or one of its successor institutions (see below), but this is a recent usage, and Sorbonne has actually... Encyclopædia Britannica, the eleventh edition The Encyclopædia Britannica Eleventh Edition (1910–1911) is perhaps the most famous edition of the Encyclopædia Britannica. ... The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ...


Further reading

  • Rue, Leonard Lee, III.
    • "The World of the Beaver", Lippincott Company, 1964.
    • "Beavers", 2002. ISBN 0896585484

External links

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  Results from FactBites:
 
Beaver - Free Encyclopedia (988 words)
Beavers are nearly allied to the squirrels (Sciuridae), agreeing in certain structural peculiarities of the lower jaw and skull.
Beavers are sociable animals, living in streams, where, so as to render the water of sufficient depth, they build dams of mud and of the stems and boughs of trees felled by their powerful incisor teeth.
Fossil remains of beavers are found in the peat and other superficial deposits of England and the continent of Europe; while in the Pleistocene formations of England and Siberia occur remains of a giant extinct beaver, Trogontzerium cuvieri, representing a genus by itself.
  More results at FactBites »

 
 

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