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Arvicolinae

Arvicolinae

Fossil Range: Late Miocene - Recent
see text Arvicolinae is a subfamily of rodents that includes the voles, lemmings, and muskrats. Its closest relatives are members of the other subfamilies in the Cricetidae, the hamsters and New World rats and mice. Sometimes the subfamily Arvicolinae is placed in the family Muridae along with all other members of the superfamily Muroidea. It is also sometimes referred to as Microtinae or is recognized as a family, Arvicolidae.

Description

The arvicolines are most easily identified based on their molar teeth, which show prismatic cusps consisting of alternating triangles. These molars are ever-growing and are well adapted to a herbivorous lifestyle. Arvicolines are Holarctic in distribution and represent one of the only major muroid radiations to reach the New World via Beringia. The other are the three subfamilies of New World rats and mice. Arvicolines do very well in the subnuvial zone beneath the winter snowpack and persist throughout winter without needing to hibernate. They are also characterized by extreme fluctuations in population size. Most arvicolines are small, furry, short tailed voles or lemmings, but some such as Ellobius and Hyperacrius are well adapted to a fossorial lifestyle. Others, such as Ondatra, Neofiber, and Arvicola have evolved a larger body size and associated with an aquatic lifestyle. Some authorities have placed the zokors within the Arvicolinae, but they have been shown to be unrelated. The subfamily Arvicolinae contains seven tribes, 26 genera, and 143 species.

Classification

- Subfamily Arvicolinae - voles, lemmings, muskrats
- Tribe Arvicolini
- Genus Arvicola - water voles
- Genus Microtus - voles
- Genus Lemmiscus - sagebrush vole
- Genus Blanfordimys
- Genus Chionomys
- Genus Proedromys
- Genus Volemys
- Genus Lagurus - steppe vole
- Genus Eolagurus - yellow steppe lemming
- Tribe Ondatrini - muskrat
- Genus Ondatra - muskrat
- Tribe Myodini
- Genus Arborimus - tree voles
- Genus Phenacomys - heather voles
- Genus Dinaromys - voles from the Dinaric Alps
- Genus Hyperacrius - voles from Pakistan
- Genus Alticola - voles from Central Asia
- Genus Eothenomys - voles from East Asia
- Genus Myodes - red-backed voles
- Tribe Prometheomyini - Prometheus mouse
- Genus Prometheomys - Prometheus mouse
- Tribe Ellobiini - mole voles
- Genus Ellobius - mole voles
- Tribe Lemmini - true lemmings
- Genus Synaptomys - bog lemmings
- Genus Lemmus - lemmings
- Genus Myopus
- Tribe Neofibrini
- Genus Neofiber - round-tailed muskrat
- Tribe Dicrostonychini - collared lemmings
- Genus Dicrostonyx - collared lemmings

References

- McKenna, M. C. and S. K. Bell. 1997. Classification of Mammals above the Species Level. Columbia University Press, New York.
- Steppan, S. J., R. A. Adkins, and J. Anderson. 2004. Phylogeny and divergence date estimates of rapid radiations in muroid rodents based on multiple nuclear genes. Systematic Biology, 53:533-553. Category:Muroid rodents Category:Voles and lemmings

Miocene

The Miocene epoch is a period of time that extends from about 23 to 5.3 million years before the present. As with other older geologic periods, the rock beds that define the start and end are well identified, but the exact dates of the start and end of the period are uncertain. The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words meion (less) and ceno (new) and means "less recent" because it has 18% (less than the Pliocene) of modern sea invertebrates. The Miocene follows the Oligocene Epoch and is followed by the Pliocene Epoch. The Miocene is the first epoch of the Neogene period. The Miocene boundaries are not set at an easily identified worldwide event but rather at regional boundaries between the warmer Oligocene and the cooler Pliocene.

Miocene Subdivisions

The Miocene faunal stages from youngest to oldest are: The subdivisions within the Miocene are defined by the relative abundance of different species of calcareous nanofossils (calcite platelets shed by brown single-celled algae) and foraminifera (single-celled protists with diagnostic shells).

Miocene Climate

Climates remained moderately warm although slow global cooling that eventual led to the Pleistocene glaciations continued. Although a long-term cooling trend was well underway, there is evidence for a warm period during the Miocene when the global climate rivalled that of the Oligocene. The Miocene warming began 21 million years ago and continued until 14 million years ago, when global temperatures took a sharp drop. By 8 million years ago, temperatures dropped sharply once again, and the Antarctic ice sheet was already approaching its present-day size and thickness. Greenland may have begun to have large glaciers as early as 7 to 8 million years ago, although the climate for the most part remained warm enough to support forests there well into the Pliocene.

Miocene Paleogeography

Continents continued to drift toward their present positions. Of the modern geologic features, only the land bridge between South America and North America was absent. Mountain building took place in Western North America and Europe. Both continental and marine Miocene deposits are common worldwide with marine outcrops common near modern shorelines. Well studied continental exposures occur in the American Great Plains and in Argentina.

Miocene Flora

Grasslands underwent a major expansion as forests fell victim to a generally cooler and drier climate overall. Grasses also diversified greatly into a number of species and also caused a major increase in the biodiversity of large herbivores, including ruminants (of which modern cattle and deer belong to).

Miocene Fauna

Both marine and continental fauna were fairly modern. Only in isolated South America and Australia did widely divergent fauna exist.

Mammals

Recognizable wolves, horses, beaver, deer, camels, whales, etc. existed in the Miocene.

Birds

Recognizable crows, ducks, and owls appear in the Miocene.

Miocene Oceans

The oceans continue cooling, and brown algae plants, called kelp, proliferate, supporting new species of sea life, including otters, fish and various invertebrates.

External References

- [http://www.bbc.co.uk/beasts/changing/miocene/index.shtml BBC Changing Worlds: Miocene]
- [http://www.pbs.org/wgbh/evolution/change/deeptime/miocene.html PBS Deep Time: Eocene]
- [http://www.ucmp.berkeley.edu/tertiary/mio.html UCMP Berkeley Miocene Epoch Page] ja:中新世

Rodent

Fossil Range: Paleocene - Recent
See Classification Section The order Rodentia is the most numerous of all the branches on the mammal family tree. Currently there are, depending on the authority consulted, between 2000 and 3000 species of rodent—roughly half of all mammal species. Rodents are found in vast numbers on all continents except Antarctica (they are the only placental order other than bats (Chiroptera) to reach Australia without human introduction), most islands, and in all habitats bar the oceans. Groups commonly confused with rodents, or erroneously thought to be rodents, include the aforementioned Chiroptera (bats), Scandentia (tree shrews), Insectivora (moles, shrews and hedgehogs), and Lagomorpha (hares, rabbits and pikas) and carnivore mink. Most rodents are small. The tiny African Pygmy Mouse is only 6 cm in length and 7 grams in weight. On the other hand, the Capybara can weigh up to 45 kg (100 pounds) and the extinct Phoberomys pattersoni is believed to have weighed 700 kg. Rodents have two incisors in the upper as well as in the lower jaw which grow continuously and must be kept worn down by gnawing; this is the origin of the name, from the Latin rodere, to gnaw. These teeth are used for cutting wood, biting through the skin of fruit, or for defence. These teeth have enamel on the outside and exposed dentine on the inside, so they self-sharpen during gnawing. Rodents lack canines, and have a space between their incisors and premolars. Nearly all rodents feed on plants, seeds in particular, but there are a few exceptions which eat insects or even fish. Rodents are important in many ecosystems because they reproduce rapidly, and can function as food sources for predators, mechanisms for seed dispersal, and as disease vectors. Humans use rodents as a source of fur, as a model organism in animal testing, for food, and even in detecting landmines[http://www.theage.com.au/articles/2004/05/18/1084783512636.html?oneclick=true].

Natural History

The fossil record of rodents began after the extinction of the dinosaurs some 65 million years ago. The earliest rodents resembled squirrels and from these stem rodents, they diversified. By the end of the Eocene epoch, beavers and squirrels appeared in the fossil record. Their origins were from Laurasia, the joined continents of North America, Europe, and Asia. Some species colonized Africa, giving rise to the earliest hystricognaths. From there they rafted to South America, an isolated continent during the Oligocene and Miocene epochs. By the Miocene, Africa collided with Asia, allowing rodents such as porcupines to spread intoEurasia. During the Pliocene, rodent fossils appeared in Australia. Even though marsupials are prominent residents in Australia, it is the rodents that dominate the mammalian fauna: making up almost 25% of the mammals on the continent. Meanwhile, the Americas collided. Rodents expanded into unknown territory: mice headed south and porcupines headed north. ;Some Prehistoric Rodents :Castoroides, a giant beaver :Ceratogaulus, a horned burrowing rodent :Flores Giant Rat, a rat that grew to large size alongside small elephants and humans on the island of Flores :Giant hutias, a group of rodents once found in the West Indies :Ischyromys, a primitive squirrel-like rodent :Leithia, a giant dormouse :Neochoerus pinckneyi, a giant North American capybara that weighed 110 pounds :Phoberomys pattersoni, the largest known rodent :Telicomys, a giant South American rodent

Classification

The rodents are part of the clades: Glires (along with lagomorphs), Euarchontoglires (along with lagomorphs, primates, tree shrews, and colugos), and Boreoeutheria (along with most other placental mammals). The order Rodentia may be divided into suborders, infraorders, superfamilies and families. This is a common classification scheme:
- ORDER RODENTIA
- Suborder Sciurognathi
- Infraorder Sciurida
- Family Sciuridae: squirrels, including chipmunks & prairie dogs
- Family Aplodontiidae: mountain beaver
- Infraorder Castorimorpha
- Family Castoridae: beavers
- Infraorder Anomaluromorpha
- Family Anomaluridae: scaly-tailed squirrels
- Family Pedetidae: springhares
- Infraorder Ctenodactylomorpha
- Family Ctenodactylidae: gundis
- Infraorder Glirimorpha
- Family Gliridae (also Myoxidae, Muscardinidae): dormice
- Infraorder Geomorpha
- Family Geomyidae: pocket gophers (true gophers)
- Family Heteromyidae: kangaroo rats and kangaroo mice
- Infraorder Myodonta
- Superfamily Dipodoidea
- Family Zapodidae: jumping mice
- Family Dipodidae: jerboas
- Superfamily Muroidea
- Family Platacanthomyidae: spiny dormice
- Family Spalacidae: mole rats, bamboo rats, and zokors
- Family Calomyscidae: mouse-like hamsters
- Family Nesomyidae: climbing mice, rock mice, white-tailed rat, Malagasy rats and mice
- Family Cricetidae: hamsters, New World rats and mice, voles
- Family Muridae: true mice and rats, gerbils, spiny mice, crested rat
- Suborder Hystricognathi
- Family Laonastidae: Laotian rock rat
- Family Hystricidae: Old World porcupines
- Family Erethizontidae: New World porcupines
- Family Thryonomyidae: cane rats
- Family Petromuridae: dassie rat
- Family Bathyergidae: African mole rats
- Infraorder Caviomorpha
- Family Octodontidae: octodonts
- Family Echimyidae: spiny rats
- Family Capromyidae: hutias
- Family †Heptaxodontidae: giant hutias
- Family Myocastoridae: nutria
- Family Dasyproctidae: agoutis
- Family Dinomyidae: pacaranas
- Family Caviidae: cavies, including guinea pigs
- Family Hydrochoeridae: Capybara
- Family Chinchillidae: chinchillas and viscachas
- Family Abrocomidae: chinchilla rats
- Family Ctenomyidae: tuco-tucos

Alternate Classifications

The above taxonomy uses the shape of the lower jaw (sciurognath or hystricognath) as the primary character. This is the most commonly used approach for dividing the order into suborders. Many older references emphasize the zygomasseteric system (suborders Protrogomorpha, Sciuromorpha, Hystricomorpha, and Myomorpha). Several molecular phylogenetic studies have used gene sequences to determine the relationships among rodents, but these studies are yet to produce a single consistent and well-supported taxonomy. Some clades have been consistently produced such as:
- Ctenohystrica contains:
- Ctenodactylidae (gundis)
- Hystricognathi containing:
- Hystricidae
- An unnamed clade containing:
- Phiomorpha
- Caviomorpha
- An unnnamed clade contains:
- Gliridae
- Sciuroidea containing:
- Aplodontiidae
- Sciuridae
- Myodonta includes:
- Dipodoidea
- Muroidea The positions of the Castoridae, Geomyoidea, Anomaluridae, and Pedetidae are still being debated.

References

- Adkins, R. M. E. L. Gelke, D. Rowe, and R. L. Honeycutt. 2001. Molecular phylogeny and divergence time estimates for major rodent groups: Evidence from multiple genes. Molecular Biology and Evolution, 18:777-791.
- Nowak, R. M. 1999. Walker's Mammals of the World, Vol. 2. Johns Hopkins University Press, London.
- Steppan, S. J., R. A. Adkins, and J. Anderson. 2004. Phylogeny and divergence date estimates of rapid radiations in muroid rodents based on multiple nuclear genes. Systematic Biology, 53:533-553. Category:Mammals ko:설치류 ja:ネズミ目

Vole

Microtus
Myodes
Phenacomys
Lagurus
Arvicola ---- Arvicola A vole is a small rodent resembling a mouse but with a stouter body; a shorter, hairy tail; and smaller ears and eyes.

Description

Most vole species have rootless molars that fold into a series of triangles. Voles are one of the few rodents whose molars continue to grow during their entire life. There is little to distinguish a vole from a lemming. All rodents have incisors that grow continuously. Adult voles, depending on the species, are three to seven inches long.

Habitat

Voles live in a variety of environments. The North American meadow vole lives in networks of above-ground "runways" in grassy areas, as well as underground burrows. California's red vole lives in the tree tops.

Range

Sometimes known as field mice in America, approximately 70 species of voles can be found in Europe, Asia, North Africa and North America.

Diet

Depending on the species, the Vole's diet consists of seeds, tubers, conifers needles, bark, various green vegetation such as grass and clover, and insects.

Predators

Most carnivores such as owls, hawks, coyotes, foxes, weasels, and cats eat voles.

Age

The average life of a vole is between 3-6 months. Voles rarely live longer than 12 months. The longest lifespan of a vole ever recorded was 18 months.

Popular Culture

The character of Ratty in The Wind in the Willows is actually a water vole, not a rat. Category:Muroid rodents Category:Voles and lemmings

Lemming

:This article is about the rodent. For the computer game, see Lemmings (video game). Dicrostonyx
Lemmus
Synaptomys
Myopus

- Incomplete listing: see vole Lemmings are small rodents, usually found in or near the Arctic. Together with the voles and muskrats, they make up the subfamily Arvicolinae (also known as Microtinae), which forms part of the largest mammal radiation by far, the superfamily Muroidea, which also includes the rats, mice, hamsters, and gerbils. Lemmings mostly weigh between 30 g and 112 g (1 to 4 oz) and are about 7 cm - 15 cm (2.75 to 6 in) long. They usually have long, soft fur and very short tails. They are herbivorous, feeding mostly on leaves and shoots, grasses, and sedges in particular, but also roots and bulbs in some cases. Like many rodents, their incisors grow continuously, allowing them to exist on much tougher forage than would otherwise be possible. Lemmings do not hibernate through the harsh northern winter, but remain active, finding food by burrowing through the snow, and utilising grasses clipped and stored in anticipation. They are solitary animals by nature, meeting only to mate and then going their separate ways, but like all rodents they have a high reproductive rate and can breed rapidly in good seasons. There is little to distinguish a lemming from a vole. Most lemmings are members of the tribe Lemmini (one of the three tribes that make up the subfamily)

Population fluctuations

Lemming populations go through rapid growths and subsequent crashes that have achieved an almost legendary status, largely because of the well-known Disney Studios film, White Wilderness, which was produced in 1958 and reappeared on television at regular intervals for many years afterwards. White Wilderness popularized, using staged footage, the myth that during population booms Norway Lemmings become suicidal and leap en masse off cliffs into the sea. For this reason, the term "lemming" is often used in slang to denote those who mindlessly follow the crowd, even if destruction is the result. In fact, the behavior of lemmings is much the same as that of many other rodents which have periodic population booms and then disperse in all directions, seeking the food and shelter that their natural habitat cannot provide. (The Australian Long-haired Rat is one example.) Myths about lemmings go back many centuries, and in the 16th and 17th centuries there was much speculation in learned circles that lemmings were in fact spontaneously generated by conditions of the air. This was argued against, successfully, by the natural historian Ole Worm, who provided one of the first published dissections of a lemming. In his investigation, Worm showed that a lemming contained anatomy similar to most other rodents, including testes—a highly pointless organ were they really to reproduce, literally, out of thin air. The populations of predatory creatures like foxes and owls follow the population changes of lemmings and voles.

Classification

- ORDER RODENTIA
- Superfamily Muroidea
- Family Cricetidae
- Subfamily Arvicolinae
-
- Tribe Lemmini
-
- Dicrostonyx
-
- St Lawrence Island Collared Lemming (Dicrostonyx exsul)
-
- Northern Collared Lemming (Dicrostonyx groenlandicus)
-
- Ungava Collared Lemming (Dicrostonyx hudsonius)
-
- Victoria Collared Lemming (Dicrostonyx kilangmiutak)
-
- Nelson's Collared Lemming (Dicrostonyx nelsoni)
-
- Ogilvie Mountain Collared Lemming (Dicrostonyx nunatakensis)
-
- Richardson's Collared Lemming (Dicrostonyx richardsoni)
-
- Bering Collared Lemming (Dicrostonyx rubricatus)
-
- Arctic Lemming (Dicrostonyx torquatus)
-
- Unalaska Collared Lemming (Dicrostonyx unalascensis)
-
- Wrangel Lemming (Dicrostonyx vinogradovi)
-
- Lemmus
-
- Amur Lemming (Lemmus amurensis)
-
- Norway Lemming (Lemmus lemmus)
-
- Brown Lemming (Lemmus sibiricus)
-
- Myopus
-
- Wood Lemming (Myopus schisticolor)
-
- Synaptomys
-
- Northern Bog Lemming (Synaptomys borealis)
-
- Southern Bog Lemming (Synaptomys cooperi)
-
- Tribe Ellobiini: mole voles, 5 species
-
- Tribe Microtini: voles, 121 species
-
- Eolagurus
-
- Yellow Steppe Lemming (Eolagurus luteus)
-
- Przewalski's Steppe Lemming (Eolagurus przewalskii)
-
- Lagurus
-
- Steppe Lemming (Lagurus lagurus)
-
- 118 other species known as voles or muskrats

External link

- [http://www.cas.uio.no/Publications/Jubilee/The_lemming_cycle.pdf The lemming cycle](PDF) - HTML [http://64.233.161.104/search?q=cache:24ZpDO3p6_oJ:www.cas.uio.no/Publications/Jubilee/The_lemming_cycle.pdf here with no pics], article by Nils Christian Stenseth on the regular population cycles seen in lemmings and other northern rodents
- [http://www.anomalies-unlimited.com/Disney/Lemmings.html White Wilderness], [http://www.wildlifenews.alaska.gov/index.cfm?adfg=wildlife_news.view_article&articles_id=56&issue_id=6 Alaska Wildlife News] misrepresentation of lemming suicide explained. Category:Muroid rodents Category:Voles and lemmings

Muskrat

Fossil Range: Late Pliocene - Recent
Pliocene]] 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. Adult body length is usually between 25-40 cm long, with a strong, laterally compressed tail 20-25 cm long. The body is covered in thick, brown waterproof fur; the underparts are paler. They have partially webbed hind feet and small able hand-like front feet. The weight is up to 1700 g, about four times the weight of a Brown Rat. Swamp Bunny is a nickname for a Muskrat. It is commonly used in the Mid-Atlantic States, especially in the marsh-lands and rivers surrounding the Chesapeake Bay.

Natural habitat

They live in wetlands: ponds, lakes, marshes and river banks, hence the nickname "swamp bunny". The are very good swimmers, using their tail for propulsion in the water. They are found in Alaska, Canada, the United States and northern Mexico. Extensive burrow systems are dug in the ground adjacent to the water with an underwater entrance. In marshes, lodges are constructed from cattails and mud. They also build feeding platforms in wetlands. Muskrats help maintain open areas in marshes, which helps to provide habitat for aquatic birds. These animals are most active at night or near dawn and dusk. They feed on cattails and other aquatic vegetation, freshwater mussels, frogs, crayfish and small turtles. Their predators include mink, foxes, coyotes, wolves, lynx and large owls. They are also trapped for their fur and, in some communities, for their meat. Trapping for their fur is largely limited to the northern US states, as the most common means of trapping is by placing a trap inside their frozen hut reached via an ice covered body of water. The male muskrat marks his territory with a strong musky secretion which gives this animal its name. Females have 2 to 3 litters of 6 to 8 young. Muskrat populations appear to go through a regular pattern of rise and dramatic decline spread over a 6 to 10 year period. While much wetland habitat has been eliminated due to human activity, new muskrat habitat has been created by the construction of canals or irrigation channels and the muskrat remains common and wide-spread.

Muskrat as an exogenous species in Europe

At the beginning of the 20th century (around 1905), the muskrat was introduced in the European wildlife by fur traders who thought to make a profit with the animals. Some animals escaped, other were set loose after it turned out that the business wasn't profitable. Due to their rapid breeding and lack of predators, the species quickly spread out over continental Europe, from the North Sea to the Black Sea and beyond.

Hunting Muskrat

European countries such as Belgium and The Netherlands consider it to be a pest which must be exterminated. Therefore the animal is hunted to keep the population down. The main reason the animal is considered a pest is because its burrowing causes damage to dykes and levees. Many people who have muskrats in their ponds (espesially dammed ponds) dislike muskrats because they burrow into dams and levees, eventually causing structual problems. Therefore muskrats are hunted year-round to control their numbers, although it is difficult to do so effectively since they breed so rapidly. Often traps are set to catch them, in addition to hunting. In Belgium and The Netherlands, killed animals are sometimes sold to restaurants and served as waterkonijn (water rabbit).

External links

- [http://my.net-link.net/0B/93/vaneselk/muskrat Everything Muskrat]
- [http://www.hww.ca/hww2.asp?id=96 Hinterland Who's Who]
- [http://www.monroeboatclub.org/amuskratbecomesafish.htm How the Muskrat Became a Fish]
- [http://www.freep.com/news/cfp/3/vrat11v_20041111.htm Mouthwatering muskrat meals to go, Detroit Free Press]
- [http://www.muskrat.com/index.htm#MuskratLegends How Muskrat Created the World - Native American Legends] Category:Voles and lemmings ja:ジャコウネズミ

Hamster

Fossil Range: Middle Miocene - Recent

- Cricetus
- Mesocricetus
- Cricetulus
- Phodopus A hamster (German) is a rodent belonging to subfamily Cricetinae. The subfamily contains about 18 species, classified in six or seven genera. Most have expandable cheek pouches, which reach from their cheeks to their shoulders. Hamsters are sometimes used in lab experiments (because they can reproduce quickly), along with rats, mice, and many other rodents.

Species of hamsters

The best known species is the Syrian Hamster, also known as the Golden Hamster, Mesocricetus auratus, which is commonly kept as a pet. Two other varieties of hamster are also growing in popularity as pets, the closely related Dwarf Campbell's Russian (Phodopus campbelli) and the Winter White Russian Hamsters (P. sungorus). Two further species (the Chinese Hamster Cricetulus curtatus and the Roborovski Hamster (Phodopus roborovskii) can be found on occasion. Also extremely popular since its discovery around 1985 or 1986 is a mutation of the Syrian Hamster known as the "Black Bear" hamster; more docile than most hamsters, it is black with a white patch of fur at the neck. The reported docility of the Black Bear hamster is not however related to the black color, but rather to the more careful breeding of these animals. A badly bred "Black Bear" hamster can be just as aggressive as a normal golden hamster.

Hamsters as pets

Roborovski Hamster The hamster kept as pet most often is the Syrian Hamster, also called Golden Hamster. So-called Teddybear or Black bear hamsters are breeds of syrian hamsters. But also four species of smaller hamsters are popular pets, often called dwarf hamsters. These are Roborovski hamster, (Phodopus roborovskii) often called Roborovski, the chinese striped hamster (Cricetulus griseus) and the two subspecies of Phodopus sungorus, the winter white russian dwarf hamster (Phodopus sungorus sungorus) and Russian Campbell's dwarf hamster (Phodopus sungorus campellii). The care of the dwarf hamsters is similar to that of the syrian hamster, but there are differences in feeding and housing needs and temperament. Winter whites and Campell's are fairly popular, in the US the campells more so than the winter whites, while it's other way round in Europe. Roborovski and Chinese striped Hamsters are somewhat more difficult to breed and keep, they are usually only available from breeders, and therefore limited to serious rodentia fans. Roborovski are especially not suitable for children. Hamsters are nocturnal by nature. Many people prefer them to rats, given rats' unsavory reputation (undeserved as pets). Unlike rats, they are not particularly good at learning tricks but can be entertaining to watch. They are also much smaller than guinea pigs, although equally as furry and appealing, so are more appropriate for homes with limited space.

Housing

guinea pig Hamsters can be kept both in cages and in terrariums, both of which are available in pet stores. Cages are easier to carry, their bars can be used for climbing, and they usually include a convenient front door. On the other hand, glass boxes keep hamsters from throwing litter out of their cages, provide a better view into the hamster's home, and create a quieter and more sheltered interior. In general, terrariums are more appropriate for dwarf hamsters, which are more sensitive to a disquieting environment and which would otherwise need very narrow-grid bars to keep them from slipping through. Middle-sized hamsters, such as the Syrian Hamster, especially enjoy climbing the cage walls. This, however, is extremely dangerous because the hamster can get its leg caught in the bars and fracture it. On the other hand, bars (the cage should have horizontal and vertical bars) are more open to the outside world; cages might be a better choice for these hamsters. Despite the hamster's small size, appropriate housings should always have a floor space of at least one square foot. Glass boxes must not be higher than their width to allow for a sufficient air circulation. Although smaller in size, dwarf hamsters should have bigger housings than their larger relatives, at least 80 cm by 40 cm (2 feet by 4 feet). The reason for this is that the dwarfs are very active, running and digging a lot, but they often cannot be taken outside their houses for long, because they are not comfortable there and, due to their smaller size, are more endangered when leaving their domicile. Usually hamsters with a bigger and more interesting home will live longer and provide more visual entertainment. In addition to buying the common housings sold in stores, you can also build customized dwellings. In this case, use only materials that are not dangerous to the animals. Plywood and wood from conifers is not suitable, because hamsters gnaw at their houses and both glue and resin are poisonous for them. Using standard water-soluble white wood glue to join pieces of solid wood, such as birch or beech wood, creates a safe environment for the hamster, although you must frequently check that the hamster is not gnawing through the wood. You can also equip a purchased cage with several intermediate levels, connected using stairs. Using wire grid for these platforms instead of solid wood causes serious injuries and is therefore not recommended. The narrow and smooth plastic toy housings that can be found in some stores are usually not appropriate as the sole habitat for hamsters. The tight tubes are enclosed, preventing sufficient air circulation, and the plastic surfaces, while easily cleanable, cannot absorb the hamster's urine like natural materials. The result is a damp and uncomfortable climate that is a perfect habitat for germs and fungi. In addition, synthetic materials are unhealthy when used for gnawing, making plastic tubes, "space stations", and houses an improper and unnatural (though often expensive) permanent home for hamsters. Reserve these habitats for supervised play and activity. The perfect place for the hamster's home is a well-lit room of constant, moderate temperature (18 to 26°C, 64 to 80°F), in a place out of strong sunlight that could cause dangerous heating. Especially when wire cages are used, it is also important to avoid drafts. Though they cannot see very far, hamsters become more relaxed and curious when positioned somewhat above the ground (at least 65 cm (2 feet)), from where they can perceive their surroundings. Cover the inside of the hamster's residence, including all intermediate levels, with a sufficiently thick layer of wooden litter for rodents, available in pet stores. Although alternative materials may work as well, most of these bear additional threats. Cat litter is dangerous, because gnawing and eating the chunks is deadly. Cedar and pine based litter/bedding contain an aromatic oil (phenols) which will irritate a hamster's respiratory system so avoid those as well. Litter made from recycled paper/pulp works well to absorb odours and is safe for hamsters. Hamsters are nest builders and a steady supply of fresh strips of tissue or newspaper (with soy-based ink) allows them to build a secure and comfortable spot in a corner of their enclosure or in their hiding house. Hay, from shops or even fresh from the garden, is also a valuable building material for cozy hamster nests, which, as an additional bonus, is also perfectly edible. A sand bath can provide a hamster with entertainment and helps them groom. In the desert (their natural habitat), hamsters will roll around in the sand, which cleans their coat and prevents it from getting too oily. Dwarf hamsters in particularly enjoy this activity. Be sure to use a dish that will not tip over. Heavy ceramic and metal dishes are preferred. You can fill the dish with fine sand. Avoid sand that is powdery or dusty as it will pose a hazard to a hamster's respiratory system as well. Regular cleaning of a hamster's home is crucial for the hamster's health. The home must be cleaned at least once a week by replacing the soiled bedding where necessary. Hamsters are fairly neat in their bathroom habits; if their enclosure is regularly cleaned, they choose one small location in which to urinate and defecate, making the cleaning simple. Small hamsters may require slightly less-frequent cleaning (perhaps once every two weeks), and may have many (usually hidden) places used as toilets. Another important component of a hamster's home is a hiding place where the animal can rest during the day. Not all commercially available houses are adequate. The houses should be of sufficient size and be closed on at least two sides. The same building materials are appropriate for these as for the larger cages, although even a small cardboard box will work (and which will have to be regularly replaced). Some houses add features such as a removable roof that helps to take away collected food (especially perishable items). Syrian hamsters are solitary animals and have to be kept alone once they are mature (around 4 weeks and above). Dwarf hamsters are more likely to accept another house mate. While sometimes two or more animals can live peacefully within one home, there can be bloody fights, so separate them as soon as they fight. In their natural habitat, there is substantially more empty space so that each hamster can have its own large territory. If more than one hamster is to live in a cage, then the cage must be larger (at least 40cm x 40cm per hamster) and there must be separate hiding houses for each animal. In any case, even after a long period of peaceful coexistence or even mating, there can be violent biting. In this situation, the hamsters should be separated immediately. Note also that, if a male and female hamster live together without fighting, then they will usually reproduce rapidly, thereby causing more space problems.

Gnawing

Despite their cuddly appearance, hamsters have long, thin, sharp teeth that can pierce a finger that is mistaken for a carrot or for a predator. When they are accustomed to being handled and are not startled, however, they are not inclined to bite and can be placed in the custody of responsible school-age children. Like many rodents, their teeth grow continuously and they must have appropriate things to chew on to relieve their instinctive gnawing and to help keep the teeth at a healthy length. They will gnaw on whatever is available, so they must be kept in enclosures that they cannot chew through. When the hamster is kept in or near a bedroom, their nocturnal nature combined with their gnawing habit can become distracting.

Exercise and Entertainment

fungi Like all pets, hamsters need exercise and entertainment to maintain their physical and mental health. An exercise wheel allows hamsters to run full speed to their hearts' content, and is a must. As more elaborate enclosures including additional toys such as plastic or wooden tubes that somewhat mimic the burrows that they might have in the wild and allow their owners to enjoy their activities. Most commercial exercise wheels marketed for hamsters have rungs which are not suitable for hamsters due to the fact that a hamster could get injured in one. Clear plastic hamster balls or cars are available, into which the hamster is placed and then, by its own action, explores an entire house or yard. Use these toys only under supervision and use common sense. Unsupervised hamsters in these toys can become trapped against furniture and panic or they can roll down stairs, injuring themselves. Do not leave them in these toys for extended periods, especially on warm days, and make sure to remove them frequently and allow them access to water or fresh fruits or vegetables. Toys should always invite the hamster to explore and use them at its own will, without forcing or violence. They should only be left in a hamster ball for 10-15 minutes at the most or they can dehydrate. If they are handled frequently, hamsters enjoy being out of their enclosures and having the opportunity to explore. They can also become very tame if handled frequently. Syrian hamsters will be tame for life once they are tamed, but if neglected, dwarf hamsters will become mean and will bite. However, they must be kept away from holes in the wall or in large pieces of furniture, because they will seek out the dark and burrow-like confines of those areas and it can be difficult or impossible to convince them to come out again.

Food

Pet stores can provide basic food for hamsters that provides their nutritional needs, but they also enjoy fresh vegetables and fruits, bird seed, and even living insects, which make up an important part of their natural diet. However, not all foods are suitable for hamsters and some , such as sweets made for humans or poisonous plants like the leaves of the tomato, may be most dangerous for the hamster's health. Almonds and citrus fruits are also toxic to all hamsters. Dwarf hamsters are susceptible to diabetes, and should not have high sugar foods, such as fruits and corn. Like with most other animals (and humans), it is not true that hamsters can decide which food is good for them and they will usually eat anything that is offered. Hamsters should also always have fresh water available. Appropriate drinking devices can be found in stores. Being small animals that are adapted to the life in arid environments, hamsters can also ingest all necessary liquid via sufficient amounts of watery vegetables, such as cucumber, without any negative effects. However, providing water is usually more convenient and can be an easy way to add medication or vitamins to the hamsters diet. Both water and vegetables must be fresh and have to be exchanged frequently, usually once a day. Water must not be given in open jars, since it is likely to be polluted and because wetness is generally very unhealthy for hamsters (that clean themselves very carefully without the need of additional water). In detail, the solid food components can be divided into three categories: dry, fresh, and animal food. Dry food makes up the bulk of a hamster's diet. Besides the standard rodent food sold in pet stores, most other kinds of seeds, kernels, and nuts can be given. Care should be taken to limit the amount of fat contained within the diet. Especially sunflower seeds, nuts, and sesame are the most nutritious and are to be considered as a treat rather than as basic food. All kinds of grain, rice, noodles (dry), dry peas and lentils on the other hand can be provided more readily: about 120 g for a medium hamster and, depending on size, about half the amount for a dwarf hamster is sufficient. Bread and similar bakery products contain many ingredients (e.g. yeast) that can trouble the hamster's digestion system. They should be given in small amounts for gnawing or be replaced by special wafers as found in pet stores. All dry food should be appropriate in size. Especially small hamsters often cannot cope well with large seeds, even if they are sold under the label "hamster food". Bird food like millet is a noteworthy alternative for small hamsters. Hay, although also belonging to the dry food category, can be provided in large amounts at any time. It does not contain notable amounts of fat, still is liked by most hamsters, supports the hamster's digestion system, serves as a hiding place, and is often used for nest building. In addition it is cheap and can even be produced in your own garden easily. Fresh food is also an important part of the hamster's diet. As mentioned above, cucumber is a good supplement of water. Fresh grass, carrot, any kind of lettuce except iceberg, leaves and even branches of (non-poisonous) plants are also no problem in general. However, no conifer wood must be fed since resin is poisonous for hamsters. In smaller amounts, grown hamsters also appreciate apple, pear, sweet paprika, banana, mango, and strawberry. Too many sweet fruits on the other hand are not healthy. All kinds of cabbage should be avoided, since they may cause flatulence, which is quite dangerous for the hamster's sensitive digestion system. It is also dangerous to feed your hamster citrus fruit of any kind. All hamsters should be given a more conservative diet. If accepted, herbs can also help to strengthen the hamster's health, though they cannot replace a veterinarian in case of a disease. Daisies (the flowers, not the stems or leaves) and dandelions are likewise appreciated. Plants used for hamster foods should never be placed near open windows because hamsters are more sensitive to chemical pollutions, due to their small body weight. Finally animal food is a major component of some hamsters' natural food. As pets, a large part of this can be replaced by dry food. Still, hamsters need some animal proteins for their health. While some people like to provide living insects from pet stores to their hamsters, others will prefer to give them dry dog biscuits. Some hamsters are known to accept yoghurt (natural, without sweet ingredients) or soft cheese (low fat, not too salty), and in any case egg noodles are usually taken gratefully. If (dry or soft) dog or cat food is given, then the fat content has to be checked carefully. Furthermore, it must not contain molasses, which would harm the hamster. In addition, a special salt stone (available in pet stores) belongs in every hamster cage. Although this huge amount of mineral salt is hardly used up by generations of hamsters, it is necessary for their life. Vitamin additives for rodents are not required and usually fresh vegetables are to be preferred. If the hamster is diseased or ill-nourished, vitamins or medications may be needed. It might be noted that many hamsters tend to carry away food from their food source (by carrying it in their cheek pouches) and hoard it away in a cache hidden somewhere inside their container. These caches, when combined with hamster urine or a leaky water source and poor airflow, can grow mold or start to rot, creating a hazardous environment for the hamster. To keep this from happening, clean hamster cages frequently. It is because of this behavior that hamsters got their name. The German word for hoard is "hamstern." There are also many foods that a hamster should never eat. This includes all kinds of human sweets, such as chocolate or candy, which are unhealthy and even dangerous. Furthermore, poisonous plants (also check indoor plants if the hamster is taken outside its housing) constitute a considerable danger. Other than this, mainly the various unhealthy and chemically treated products usually consumed by humans can cause problems. Campbells dwarf hamsters are especially sensitive to Diabetes mellitus, and other dwarf hamster species may be somewhat sensitive too. Diabetes mellitus in hamsters is often caused by intake of simple sugar. Therefore it is essential to avoid hamster food and snacks containing molasses, honey, sugar, fruit sugar or other sweet stuff. Intake of sweet fruit should be limited to small snacks. Even with golden hamsters it may be useful to follow these guideline in order to avoid overweight and digestion disturbances.

Reproduction and longevity

fruit sugar Hamsters typically live no more than two to three years in captivity, less than that in the wild. Because of their short life expectancy, hamsters mature quickly and can begin reproducing at a young age (two months). Left to their own devices, hamsters will produce several litters a year with several babies in each litter. Male and female hamsters are therefore usually kept in separate enclosures to prevent the addition of unwanted offspring. After a female hamster mates, there is a gestation period of 16-18 days before it will give birth. Following birth, the male hamster is likely to eat some of the pups. The female may act agressively toward the male during the gestation period and may kill it to protect the cubs. The average litter is about 7, but can be as great as 24, which is the maximum number of pups that can be contained in the womb. The mother hamster will gather all the pups into a nest which it built. They will be hairless, have closed eyes, nurse from their mother, and move very little. After about a week, they will begin to wander from the nest and eat solid food. After a total of three weeks, the pups will be weaned and can leave the nest for good. When seen from above, a sexually mature female hamster has a trim tail line; a male's tail line bulges on both sides.

Classification of hamsters

Taxonomists currently disagree about the most appropriate placement of the subfamily Cricetinae within the superfamily Muroidea. Some place it in a family Cricetidae that also includes voles, lemmings, and New World rats and mice; others group all these into a large family called Muridae. The following list of species may not be complete.
- Subfamily Cricetinae
- Genus Mesocricetus - Golden hamsters
- Syrian Hamster (Mesocricetus auratus); also Golden Hamster.
- Turkish Hamster (Mesocricetus brandti); also called the Brandts' Hamster, Azerbajaini Hamster
- Georgian Hamster (Mesocricetus raddei); also Ciscaucasian Hamster
- Romanian Hamster (Mesocricetus newtoni)
- Genus Phodopus - Dwarf hamsters
- Djungarian Hamster (Phodopus sungorus); two subspecies are recognised, the Siberian Hamster proper or White Russian Hamster (Phodopus sungorus sungorus), and Campbell's Dwarf Russian Hamster (Phodopus sungorus campbelli)
- Roborovski Hamster (Phodopus roborovski); sometimes known as the Mongolian Hamster, although this causes confusion with Cricetulus curtatus
- Genus Cricetus
- European Hamster (Cricetus cricetus); also called the Common Hamster or Black-bellied Field Hamster
- Genus Cricetulus
- Striped Dwarf Hamster (Cricetulus griseus); also Chinese striped hamster, Chinese hamster
- Mongolian Hamster (Cricetulus curtatus)
- Long-tailed Hamster (Cricetulus longicaudatus)
- Tibetan Hamster (Cricetulus kamensis)
- Kazakh Hamster (Cricetulus eversmani); also Eversmann's Hamster
- Greater Long-tailed Hamster (Cricetulus triton); also Greater Longtailed Hamster, and the Korean Hamster
- Ladak Hamster (Cricetulus alticola)
- Armenian Hamster (Cricetulus migratorius); also called the Migratory Grey Hamster
- Gobi Hamster (Cricetulus obscurus)
- Transbaikal Hamster (Cricetulus pseudogriseus)

Animals that are not really hamsters

Note that there are some rodents sometimes called "hamsters" that are not currently classified in the hamster subfamily Cricetinae. These include the Maned Hamster or Crested Hamster, which is really the Maned Rat (Lophiomys imhausi), although not nearly as marketable under that name. Others are the mouse-like hamsters (Calomyscus spp.), and the white-tailed rat (Mystromys albicaudatus).

Hamsters in popular culture

As the hamster is generally considered a cute animal, it is often anthropomorphized when found in popular culture. Famous examples of this include the anime Hamtaro and the Hamster Dance. Rennets are not a type of hamster. A spoof web site [http://savetherennets.com] has popularised rennets as so, building on the cuteness of hamsters.

External links

- [http://www.hamsoc.org.uk The Hamster Society (UK)]
- [http://www.hamsterhouse.com/ Popular Hamster Chat Forum]
- [http://www.britishhamsterassociation.org.uk The British Hamster Association]
- [http://www.hamsterhideout.com Hamster Hideout]
- [http://www.petwebsite.com/about_hamsters.htm About Hamsters on Petwebsite.Com]
- [http://www.hamsterific.com/ Hamsterific.Com]
- [http://www.geocities.com/CalHamAssoc/index.html California Hamster Association]
- [http://communities.msn.com/Hamstersgalore Hamsters Galore! Community website]
- [http://www.rodentrefuge.co.uk/hamsterfaq.html The Alt.Pets.Hamsters newsgroup FAQ]
- [http://www.hampsterdance2.com/ Hampsterdance2]
- [http://www.petwebsite.com/turkish.htm The Turkish hamster]
- [http://www.petwebsite.com/mouse.htm Mouselike hamster]
- [http://hamsterhat.com Hamster Hat]
- [http://www.savetherennets.com Save the Rennets] ---- Category:Animals kept as pets Category:Muroid rodents Category:Hamsters Category:German loanwords ko:햄스터 ja:ハムスター

Muridae

Fossil Range: Early Miocene - Recent
Deomyinae
Gerbillinae
Lophiomyinae
Murinae Muridae is the largest family of mammals. It contains over 600 species found naturally throughout Eurasia, Africa, and Australia. They have been introduced worldwide. The group includes true mice and rats, gerbils, and relatives. The family name Muridae is sometimes used in a broader sense to include all members of the superfamily Muroidea. The Murids are classified in 4 subfamilies, around 140 genera and approximately 650 species.

Subfamilies

- Deomyinae (spiny mice, brush furred mice, link rat)
- Gerbillinae (gerbils, jirds and sand rats)
- Lophiomyinae (Crested Rat)
- Murinae (Old World rats and mice including the vlei rats)

References

- Jansa, S. A. and M. Weksler. 2004. Phylogeny of muroid rodents: relationships within and among major lineages as determined by IRBP gene sequences. Molecular Phylogenetics and Evolution, 31:256-276.
- Michaux, J., A. Reyes, and F. Catzeflis. 2001. Evolutionary history of the most speciose mammals: molecular phylogeny of muroid rodents. Molecular Biology and Evolution, 17:280-293.
- Steppan, S. J., R. A. Adkins, and J. Anderson. 2004. Phylogeny and divergence date estimates of rapid radiations in muroid rodents based on multiple nuclear genes. Systematic Biology, 53:533-553. Category:Rodents Category:Muroid rodents

Family (biology)

In biological classification, family is one of the most important ranks, next only to species and genus. See:
- rank (botany)
- rank (zoology)
- Virus classification rank13 rank13 rank13 als:Familie (Biologie) ms:Famili

Molar

Molar may refer to:
- Molar (tooth), the fourth kind of tooth in mammals.
- Molar (M), a unit of concentration, or molarity, of solutions. See also Mole (unit) and Molar volume
- Molar, Tarragona, a village in the comarca (county) of Priorat, province of Tarragona in the autonomous region of Catalonia, Spain.
- Molar behavior, or molara, larger units of behavior in psychology.

Molar

Herbivore

In zoology, a herbivore is an animal that is adapted to eat primarily plant matter (rather than meat). Although such animals are sometimes refered to as being vegetarian, this term is more properly reserved for humans who choose not to eat meat as opposed to animals that are unable to. Herbivores can be further classified into various sub-groups, such as frugivores, which eat mainly fruit; or folivores, which specialize in eating leaves. This specialization is far from universal, however, and many fruit- and leaf-eating animals also eat other parts of plants, notably roots and seeds. The diets of some herbivorous animals vary with the seasons, especially in the temperate zones, where different plant foods are most available at different times of year.

Animals that are true herbivores

The following are herbivorous animals in nature. Most can digest meat in artificial conditions (feedlots) with adaptation.
- Bovids (such as cows, sheep, goats, buffalo, antelopes, bison, gazelles, and moose)
- Horses (including all members of the horse family such as domestic horses, donkeys, and zebras)
- Deer
- Elephants
- Rhinos
- Hippos
- Giraffes
- Gorillas
- Orangutans
- Pandas
- Some rodents such as guinea pigs, porcupines, beavers, and capybaras
- Rabbits
- Tortoises and turtles
- Grasshoppers and many other insects
- Snails and slugs

External links

- [http://www.sankey.ws/senecio.html the herbivore defenses of Senecio viscusus] Category:Eating behaviors ms:Maun ja:草食動物 simple:Herbivore

NEW WORLD

:New World is also a 1990 album by Kelly Family. New World is an album by Do As Infinity, released 2001.

Tracklist

# new world # GURUGURU # Desire # We Are. # Snail # 永遠 (Eien) (Eternity) # rumble fish # Holiday # 135 # Wings 510 # SUMMER DAYS # Yesterday & Today (Strings Orchestral Version) Category:2001 albums

Beringia

, site of former land bridge between Asia and North America]] The Bering land bridge, also known as Beringia, was a land bridge roughly 1600 km (1000 miles) north to south at its greatest extent, which joined present-day Alaska and eastern Siberia at various times during the ice ages. Biogeographical evidence can prove this land bridge existed far earlier. Similar dinosaur fossils have been found between Asia and North America. For instance the dinosaur Saurolophus was found in both Mongolia and western North America. Relatives of Troodon, Triceratops, and even Tyrannosaurus rex all came from Asia. Fossils in China demonstrate a migration of Asian mammals into North America around 55 million years ago. By 20 million years ago, evidence in North America shows a further interchange of mammalian species. Some, like the ancient saber-toothed cats, have a reoccuring geographical range: Europe, Africa, Asia, and North America. The only way they could reach the New World is through the Bering land bridge. Had this bridge not existed at that time, the fauna of the world would be very different. For instance horses, dogs, and camels would inhabit only the Americas and nowhere else. The Bering Strait, the Chukchi Sea to the north and the Bering Sea to the south, are all shallow seas. During previous cycles of global cooling, such as the most recent ice age, enough sea water became concentrated in the ice caps of the Arctic and Antarctic that the subsequent drop in eustatic sea levels exposed shallow sea floors. Other land bridges around the world have been created and re-flooded in the same way: approximately 14,000 years ago, mainland Australia was linked both to New Guinea and to Tasmania, the British Isles were an extension of continental Europe via the English Channel, and the dry basin of the South China Sea linked Sumatra, Java and Borneo to the Asian mainland. The Bering Land Bridge is significant for several reasons, not least because it enabled human migration to the Americas from Asia about 12,000 years ago. Recent studies have indicated that of the people migrating across this land bridge during that time period, only 70 left their genetic print in modern descendents, a minute effective founder population— easily misread as though implying that only 70 people crossed to North America. Sea-going coastal settlers may also have crossed much earlier, but scientific opinion remains divided on this point and the coastal sites that would offer further information now lie submerged in up to a hundred metres of water offshore. Land animals were able to migrate through Beringia as well, bringing mammals that evolved in Asia to North America, mammals such as lions and cheetahs, which evolved into now-extinct endemic North American species, and exporting camelids that evolved in North America (and later became extinct there) to Asia. The rise and fall of global sea levels has exposed the land bridge in several periods of the Pleistocene. The bridging land mass called "Beringia" is believed to have existed both in the glaciation that occurred before 35,000 BC and during the more recent period 22,000-7,000 YBP. By c. 6000 YBP the coastlines had assumed approximately their present configurations. Beringia constantly transformed its ecology as the changing climate affected the environment, determining which plants and animals were able to survive. The land mass could be a barrier as well as a bridge: during colder periods, glaciers advanced and precipitation levels dropped. During warmer intervals clouds, rain and snow altered soils and drainage patterns. Fossil remains show that spruce, birch and poplars once grew beyond their northernmost modern range today, indicating there were periods when the climate was warmer and wetter. Mastodon, that depended on shrubs for food, were uncommon in the open dry tundra landscape characteristic of Beringia during the colder periods. In this tundra, mammoths also flourished.

External links

- [http://www.nps.gov/bela/ Bering Land Bridge National preserve]
- [http://www.nps.gov/akso/beringia/whatisberingia2.htm What is Beringia?]
- [http://weber.ucsd.edu/~dkjordan/arch/beringia.html#top D.K. Jordan, "Prehistoric Beringia"]
- [http://www.ngdc.noaa.gov/paleo/parcs/atlas/beringia/lbridge.html Paleoenvironmental atlas of Beringia:] includes animation showing the gradual disappearance of the Bering land bridge
- [http://www.beringia.com/ Yukon Beringia Interpretive Centre]
- [http://www.geo.umass.edu/projects/chukotka/berhome.html Paleoenvironments and Glaciation in Beringia]
- [http://spp.pinyin.info/abstracts/spp039_precolumbian_crossings.html introduction to "A Material Case for a Late Bering Strait Crossing Coincident with Pre-Columbian Trans-Pacific Crossings"]
- [http://www.ncdc.noaa.gov/paleo/parcs/atlas/beringia/lbridge.html An animation of the flooding of the Bering land bridge over the last 20,000 years]

References

- Pielou, E. C., After the Ice Age : The Return of Life to Glaciated North America 1992
- Hey, Jody, 2005. "On the Number of New World Founders: A Population Genetic Portrait of the Peopling of the Americas" in PLoS Biol 2005 May 24;3(6):e193 [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15898833&query_hl=1]

Lemming

Population fluctuations

Classification

External link

Ondatra

Natural habitat

Muskrat as an exogenous species in Europe

Hunting Muskrat

External links

Arvicola

The water voles are large voles in the genus Arvicola. They are found in both aquatic and dry habitat through Europe and much of northern Asia. Head and body length are 12-22 cm, tail length is 6.5-12.5 cm, and the weight is 70-250 g. The animals may exhibit indeterminate growth. They are thick-furred and have hairy fringe on feet that improves their swimming ability.

Species

- Southwestern Water Vole - Arvicola sapidus
- European Water Vole - Arvicola terrestris

References

- Nowak, R. M. 1999. Walker's Mammals of the World, Vol. 2. Johns Hopkins University Press, London. Category:Voles and lemmings

Aquatic

The term aquatic refers to water and can be either a noun or an adjective. Dictionary definitions do not specify what kind of water, although in both general use and in the sciences, the implication is that of fresh water. The term marine is typically substituted where reference to salt water is intended.
- Lakes, rivers, streams, wetlands, and ponds are examples of aquatic environments.
- Aquatic ecology is a discipline that uses the principles and methods of ecology to study natural aquatic environments. However, the term limnology is more often used in this context.
- The term aquatics is another name for watersports.

Vole

Microtus
Myodes
Phenacomys
Lagurus
Arvicola ---- Arvicola A vole is a small rodent resembling a mouse but with a stouter body; a shorter, hairy tail; and smaller ears and eyes.

Description

Habitat

Range

Sometimes known as field mice in America, approximately 70 species of voles can be found in Europe, Asia, North Africa and North America.

Diet

Depending on the species, the Vole's diet consists of seeds, tubers, conifers needles, bark, various green vegetation such as grass and clover, and insects.

Predators

Most carnivores such as owls, hawks, coyotes, foxes, weasels, and cats eat voles.

Age

The average life of a vole is between 3-6 months. Voles rarely live longer than 12 months. The longest lifespan of a vole ever recorded was 18 months.

Popular Culture

The character of Ratty in The Wind in the Willows is actually a water vole, not a rat. Category:Muroid rodents Category:Voles and lemmings

Muskrat

Fossil Range: Late Pliocene - Recent
Pliocene]] The Muskrat or Musquash (Ondatra zibethicus), the only species in genus Ondatra, is a large aquatic