Rat

Taxobox
name = Rats
fossil_range = Early Pleistocene – Recent


image_width = 200px
image_caption = The common Brown Rat ("Rattus norvegicus")
regnum = Animalia
phylum = Chordata
classis = Mammalia
ordo = Rodentia
superfamilia = Muroidea
familia = Muridae
subfamilia = Murinae
genus = "Rattus"
genus_authority = Fischer de Waldheim, 1803
subdivision_ranks = Species
subdivision = 50 species; see text
synonyms ="Stenomys" Thomas, 1910

Rats are various medium sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus "Rattus", the most important of which to humans are the black rat, "Rattus rattus", and the brown rat, "Rattus norvegicus". Many members of other rodent genera and families are also called rats and share many characteristics with true rats.

Rats are distinguished from mice by their size; rats generally have bodies longer than convert|12|cm|in|0|abbr=on.

pecies and description

The best-known rat species are the Black Rat ("Rattus rattus") and the Brown Rat ("Rattus norvegicus"). The group is generally known as the Old World rats or true rats, and originated in Asia. Rats are bigger than most Old World mice, which are their relatives, but seldom weigh over 500 grams (1 lb) in the wild.

The term "rat" is also used in the names of other small mammals which are not true rats. Examples include the North American pack rats, a number of species loosely called kangaroo rats, and others. Rats such as the Bandicoot rat ("Bandicota bengalensis") are murine rodents related to true rats, but are not members of the genus "Rattus". The widely distributed and problematic commensal species of rats are a minority in this diverse genus. Many species of rats are island endemics and some have become endangered due to habitat loss or competition with the Brown, Black or Polynesian rat.

In Western countries, many people keep domesticated rats as pets. These are of the species "R. norvegicus", which originated in the grasslands of China and spread to Europe and eventually, in 1775, to the New World. Pet rats are Brown Rats descended from those bred for research, and are often called "fancy rats", but are the same species as the common city "sewer" rat. Domesticated rats tend to be both more docile than their wild ancestors and more disease prone, presumably due to inbreeding.

The common species are opportunistic survivors and often live with and near humans. The Black Plague is traditionally believed to have been caused by the micro-organism "Yersinia pestis", carried by the Tropical Rat Flea ("Xenopsylla cheopis") which preyed on "R. rattus" living in European cities of the day; these rats were victims of the plague themselves.

While modern wild rats can carry Leptospirosis and some other "zoonotic" conditions (those which can be transferred across species, to humans, for example), these conditions are in fact rarely found (not true in neotropical countries).Fact|date=February 2007 Wild rats living in good environments are typically healthy and robust animals. Wild rats living in cities may suffer from poor diets and internal parasites and mites, but do not generally spread disease to humans.

The normal lifespan of rats ranges from two to five years, and is typically three years.

As pets

Specially bred rats have been kept as pets at least since the late 19th century. Pet rats are typically of variants of the species Brown rat, but Black rats and Giant pouched rats are also known to be kept. Pet rats behave differently than their wild counterparts depending on how many generations they have been kept as pets. Fact|date=May 2008 Pet rats do not pose any more of a health risk than pets such as cats and dogs.cite-web|url=http://www.merckvetmanual.com/mvm/htm/bc/tzns01.htm|title=Merk Veterinary Manual Global Zoonoses Table|accessdate=2006-11-24] Tamed rats are generally friendly and can be taught to perform selected behaviors.

As subjects of scientific research

In 1895, Clark University in Worcester, Massachusetts (United States) established a population of domestic white brown rats to study the effects of diet and for other physiological studies. Over the years, rats have been used in many experimental studies, which have added to our understanding of genetics, diseases, the effects of drugs, and other topics that have provided a great benefit for the health and wellbeing of humankind. Laboratory rats have also proved valuable in psychological studies of learning and other mental processes (Barnett, 2002). A 2007 study found rats to possess metacognition, a mental ability previously only documented in humans and some primates. [cite journal | last = Foote | first = Allison L. | coauthors = Jonathon D. Crystal | title = Metacognition in the Rat | journal = Current Biology | volume = 17 | issue = 6 | pages = 551–555 | date = 20 March 2007 | url = http://www.current-biology.com/content/article/abstract?uid=PIIS0960982207009311 | doi = 10.1016/j.cub.2007.01.061] [ [http://www.sciencedaily.com/releases/2007/03/070308121856.htm Rats Capable Of Reflecting On Mental Processes] ]

Domestic rats differ from wild rats in many ways. They are calmer and less likely to bite; they can tolerate greater crowding; they breed earlier and produce more offspring; and their brains, livers, kidneys, adrenal glands, and hearts are smaller (Barnett 2002).

Brown rats are often used as model organisms for scientific research. When conducting genetic research rats are much rarer than mice. When it comes to conducting tests related to intelligence, learning, and drug abuse, rats are a popular choice due to their high intelligence, ingenuity, aggressiveness, and adaptability. Their psychology, in many ways, seems to be similar to humans. Entirely new breeds or "lines" of brown rats like the Wistar rat have been bred for use in laboratories. Much of the genome of "Rattus norvegicus" has been sequenced. [cite web | url = http://www.ensembl.org/Rattus_norvegicus/index.html | title = Genome project | accessdate = 2007-02-17 | last = | first = | date = |work = www.ensemble.org | quote = ]

As food

Rats are edible by humans and are sometimes captured and eaten in emergency situations. For some cultures, rats are considered a staple. Bandicoot rats are an important food source among some peoples in Southeast Asia. Reasons why rat meat is not more widely eaten include the strong prohibitions against it in Islamic and Jewish dietary laws, and the rat's bad reputation in many cultures.

As a food, rats are often a more-readily available source of protein than other fauna. Some African slaves in the American South hunted wood rats (among other animals) to supplement their food rations. [Otto, John Solomon; Augustus Marion Burns III. (December 1983) "Black Folks, and Poor Buckras: Archeological Evidence of Slave and Overseer Living Conditions on an Antebellum Plantation". Journal of Black Studies, Vol. 14, No. 2. pp. 185-200] The Aborigines along the coast in Southern Queensland, Australia regularly included rats in their diet. [Hobson, Keith A.; Stephen Collier. (April 1984) "Marine and Terrestrial Protein in Australian Aboriginal Diets". Current Anthropology, Vol. 25, No. 2. pp. 238-240] In the Mishmi culture of India, rats are essential to the Mishmi traditional diet, as Mishmi women may eat no meat except fish, pork, wild birds and rats. [Mills, J. P. (January 1952) "The Mishmis of the Lohit Valley, Assam". The Journal of the Royal Anthropologicalpoop Institute of Great Britain and Ireland, Vol. 82, No. 1. pp. 1-12] The United Nations Food and Agriculture Organization estimates that rat meat makes up half the locally produced meat consumed in Ghana, where cane rats are farmed and hunted for their meat.

Rats have been used as food by the poor in Cambodia, particularly when meat prices have been inflated. In late 2008, Reuters reported that the price of rat meat had quadrupled in Cambodia creating a hardship for the poor who could no longer afford it. Cambodia also exports about a metric ton of rats daily to Viet Nam as food. [ [http://www.abc.net.au/news/stories/2008/08/27/2348348.htm Poor struggle as rat meat prices soar] ]

In some cultures, rats are or have been limited as an acceptable form of food to a particular social or economic class. The Musahar community in north India commercialised rat farming as a exotic delicacy. [ [http://timesofindia.indiatimes.com/Heads_and_Tales/Rat_meat_to_be_commercialised_in_Bihar/articleshow/3351440.cms Musahar Hindus commercialise rat farming] ] In the traditional cultures of the Hawaiians and the Polynesians, rat was a common food. When feasting, the Polynesian people of Rapa Nui could eat rat, but the king was not allowed to due to the islanders' belief in a "state of sacredness" called "tapu". [Leach, Helen. (February 2003) "Did East Polynesians Have a Concept of Luxury Foods?" World Archaeology, Vol. 34, No. 3, Luxury Foods. pp. 442-457.] In studying pre-contact archaeological sites in Hawaii, archaeologists have found that the concentration of the remains of rats associated with commoner households counted for three times the animal remains associated with elite households. The rat bones found in all sites are fragmented, burned and covered in carbonized material, indicating that rats were eaten as food. The greater occurrence of rat remains associated with commoner households may indicate that the elites of pre-contact Hawaii did not consume them as a matter of status or taste. [Kirch, Patrick V.; Sharyn Jones O'Day. (February 2003) "New Archaeological Insights into Food and Status: A Case Study from Pre-Contact Hawaii." World Archaeology, Vol. 34, No. 3. pp. 484-497]

The taboo against consuming rats as food is not unique to the world's major religions or Western cultures. Both the Shipibo people of Peru and Sirionó people of Bolivia have cultural taboos against the eating of rats. [Behrens, Clifford A. (September 1986) "Shipibo Food Categorization and Preference: Relationships between Indigenous and Western Dietary Concepts". American Anthropologist, Nathan New Series, Vol. 88, No. 3. pp. 647-658.] [Priest, Perry N. (October 1966) "Provision for the Aged among the Sirionó Indians of Bolivia". American Anthropologist, New Series, Vol. 68, No. 5. pp. 1245-1247]

Rats are a common food item for snakes, both in the wild, and as pets. Captive-bred ball pythons in particular, are fed a diet of mostly rats. Rats, as food items, are available from many suppliers who supply to individual snake owners as well as to large reptile zoos.

In medicine

Rats can serve as zoonotic vectors for certain disease, such as Lassa fever and Hantavirus.

In culture

Ancient Romans did not generally differentiate between rats and mice, instead referring to the former as "Mus Maximus" (big mouse) and the latter as "Mus Minimus" (little mouse).

On the Isle of Man (a dependancy of the British Crown) there is a taboo against the word "rat." See longtail for more information.

In Eastern cultures

In Imperial Chinese culture, the rat (sometimes referred to as a mouse) is the first of the twelve animals of the Chinese zodiac. People born in this year are expected to possess qualities associated with rats, including creativity, honesty, generosity, ambition, a quick temper and wastefulness. People born in a year of the rat are said to get along well with "monkeys" and "dragons," and to get along poorly with "horses."

In Indian tradition rats are recognized as the vehicle of Lord Ganesh and a rat's statue is always found in a temple of Ganesh. In the northwestern Indian city of Deshnoke, the rats at the Karni Mata Temple are held to be destined for reincarnation as Sadhus (Hindu holy men). The attending priests feed milk and grain to the rats, of which the pilgrims also partake. Eating food that has been touched by rats is considered a blessing from god.

In Western cultures

Western associations with the rat are generally negative. For instance, "Rats!" is used as a substitute for various vulgar interjections in the English language. These associations do not draw, "per se", from any biological or behavioral trait of the rat, but possibly from the association of rats (and fleas) with the 14th-century medieval plague called the Black Death. Rats are seen as vicious, unclean, parasitic animals that steal food and spread disease. However some people in Western cultures keep rats as pets and conversely find them to be tame, clean, intelligent, and playful.

Rats are often used in scientific experiments; animal rights activists allege that treatment of rats in this context is cruel. The term "lab rat" is used, typically in a self-effacing manner, to describe a person whose job function requires that they spend a majority of their work time engaged in bench-level research (i.e. a scientist or research assistant).

"Rat" in terminology

Rats are frequently blamed for damaging food supplies and other goods, or spreading disease. Their reputation has carried into common parlance: in the English language, "rat" is often an insult. It is a term (noun and verb) in criminal slang for an informant - "to rat on someone" is to betray them by denouncing to the authorities a crime or misdeed they committed. Describing a person as "rat-like" usually implies he is unattractive and suspicious.

Among unions, "rat" is a term for non-union employers or breakers of union contracts, and this is why unions use inflatable rats. [http://nj.npri.org/nj98/07/power&privilege.htm]

Rat Poker Tours are poker tournaments where common courtesy rules are banned. Chip stealing, insults, physical violence are common and accepted as part of the game.

In religion

*In Leviticus 11:29, rats are prohibited as food. (see 'as food' above)

In popular culture

*"The Wind in the Willows" by Kenneth Grahame features literature's most famous 'rat', Ratty. Ironically, the character is not actually a bona fide rat, but rather a European Water Vole - otherwise known as a water rat, hence Ratty's given name.
*Suzanne Collins's series The Underland Chronicles is about a land underneath the surface of the earth where rats are about convert|6|ft|m tall and are generally evil.
*Roland Rat was a major TV personality in 1980s Britain.
*Mutant, man-eating rats are the monsters in James Herbert's horror novel "The Rats" and its sequels.
*A phobia of rats is used as a torture device in the novel "Nineteen Eighty-Four" by George Orwell.
*Rats are the most common enemy in Brian Jacques's "Redwall" series of anthropomorphic fantasy novels.
*In Robin Jarvis's Deptford Mice trilogy of books, many of the villains are sewer rats.
*The characters of "Mrs. Frisby and the Rats of NIMH", the television series "Ratz", Rizzo the Rat from The Muppets and Terry Pratchett's "The Amazing Maurice and his Educated Rodents" are all positive rat characters. [ [http://www.hamiltonparanormal.com/rattery/hollywood.html Hollywood Rats] ]
*Rats also appear in numerous video and computer games as killable monsters. In many of these games, rats appear much larger than normal. Examples of games where rats and giant rats are found as monsters include Baldur's Gate (I and II), Everquest, and Runescape. In these games rats are the lowest form of threat faced by new characters and are used as a form of combat training. Fact|date=September 2007
*Graffiti artist Banksy frequently uses the image of rats in his work as a symbol of disobedience to authority.
*Splinter of "Teenage Mutant Ninja Turtles" fame is a mutated rat.
*Templeton of E. B. White's children's book, "Charlotte's Web", is a Brown rat, devoid of morals, that lives on the farm, underneath Wilbur's food trough.
*A media frenzy developed in New York City 23 Feb. 2007, when a dozen rats invaded a Taco Bell, and ran unimpeded. [ [http://www.signonsandiego.com/news/nation/20070224-0052-restaurantrats.html signonsandiego.com] ]
*A "Transformers" character called Rattrap can transform into a rat.
*Malevolent rats in H. P. Lovecraft's short story "The Rats in the Walls"
*In DreamWorks and Aardman Animations' 2006 film, "Flushed Away", a pet rat is flushed down the toilet into a city in the London sewer populated by other rats.
*Disney's Pixar release, "Ratatouille", features a rat named Remy seeking to become a fine chef.
*In the 1971 film "Willard" and the 2003 remake "Willard (2003 film)".
*In the Animorphs book series by K. A. Applegate, the character David is trapped in rat morph by the other Animorphs after he betrays them.
*Spike aired "Gary the Rat", an animated series revolving around a debauched attorney named Gary Andrews who mysteriously transforms into an anthropomorphic gray rat.
*In early episodes of "South Park", Kenny McCormick's corpse was frequently gnawed upon and dragged away by rats after he died.
*In the TV series "House", House has a pet rat named Steve McQueen that he caught at his ex-girlfriend, Stacy Warner's home. He's first seen in the episode, Hunting, and later appears in Euphoria, Part 2.
*In the Belgian comic book "Le Bal du rat mort" [ " [http://fr.wikipedia.org/wiki/Le_Bal_du_rat_mort Le Bal du rat mort] " fr icon ] , which means "the Ball of the Dead Rat", police inspector Jean Lamorgue is like a pied piper who has to deliver the city of Ostend from thousands of invading rats who attack people and kill them, but in the end he fails because he is possessed by his own demons.
*In the Deltora Quest series there is a city called Hira, nicknamed the "City of Rats" because its rat population grew so much that its people were forced to flee. These rats were used by the villains to feed a giant snake monster that took control of the city.
*In the Harry Potter books, a character named Peter Pettigrew can transform at will into a rat, for which he is nicknamed Wormtail.
*In the Disney movie Lady and the Tramp, a rat craws into the baby's room, and Tramp runs into the house to save the child. The rat also squeaks in pain when Tramp bites him, like a real rat does when hurt.
*In Thomas Pynchon's novel "V.", a female rat named Veronica is introduced in chapter five as part of a sub-plot in which Father Linus Fairing lives in the sewers and preaches to a congregation of rats.
*In season 3 of "Buffy the Vampire Slayer", Amy Madison, a witch, briefly turns Buffy into a rat. Later Amy turns herself into a rat, and Willow keeps her as a pet until she learns the spell to return Amy to human form in season six.
*In the Afghan children's books series (by Assad Eslam), rats were seen as god like creatures.
*In the tabletop wargame Warhammer, the Skaven are a race of intelligent, malevolent humanoid rats.
*The Pokémon Rattata and Raticate are based on rats.
*In The Tale of Despereaux by Kate DiCamillo, Chiaroscuro is an evil rat that loves light.

Taxonomy of "Rattus"

The genus "Rattus" is a member of the giant subfamily Murinae. There are several other murine genera that are sometimes considered part of "Rattus". : "Lenothrix", "Anonymomys", "Sundamys", "Kadarsanomys", "Diplothrix", "Margaretamys", "Lenomys", "Komodomys", "Palawanomys", "Bunomys", "Nesoromys", "Stenomys", "Taeromys", "Paruromys", "Abditomys", "Tryphomys", "Limnomys", "Tarsomys", "Bullimus", "Apomys", "Millardia", "Srilankamys", "Niviventer", "Maxomys", "Leopoldamys", "Berylmys", "Mastomys", "Myomys", "Praomys", "Hylomyscus", "Heimyscus", "Stochomys", "Dephomys", and "Aethomys".

The genus "Rattus" proper contains 56 species. A subgeneric breakdown of the species has been proposed, but does not include all species. The five groups are:
*"norvegicus" group
*"rattus" group
*Australian native rat species
*New Guinea native rat species
*"xanthurus" group

The following list is alphabetical.

pecies of rats

*Genus "Rattus"

**"Rattus adustus" **"Rattus annandalei" **"Rattus argentiventer" **"Rattus baluensis" **"Rattus bontanus" **"Rattus burrus" **"Rattus colletti" **"Rattus elaphinus" **"Rattus enganus" **"Rattus everetti"

**"Rattus exulans" **"Rattus feliceus" **"Rattus foramineus" **"Rattus fuscipes" **"Rattus giluwensis" **"Rattus hainaldi" **"Rattus hoogerwerfi" **"Rattus jobiensis" **"Rattus koopmani" **"Rattus korinchi"

**"Rattus leucopus" **"Rattus losea" **"Rattus lugens" **"Rattus lutreolus" **"Rattus macleari" **"Rattus marmosurus" **"Rattus mindorensis" **"Rattus mollicomulus" **"Rattus montanus" **"Rattus mordax"

**"Rattus morotaiensis" **"Rattus nativitatis" **"Rattus nitidus" **"Rattus norvegicus" **"Rattus novaeguineae" **"Rattus osgoodi" **"Rattus palmarum" **"Rattus pelurus" **"Rattus praetor" **"Rattus ranjiniae"

**"Rattus rattus" **"Rattus sikkimensis" **"Rattus simalurensis" **"Rattus sordidus" **"Rattus steini" **"Rattus stoicus" **"Rattus tanezumi" **"Rattus tawitawiensis" **"Rattus timorensis" **"Rattus tiomanicus"

**"Rattus tunneyi" **"Rattus turkestanicus" **"Rattus villosissimus" **"Rattus xanthurus"

ee also

*Black rat
*Brown rat
*List of fictional mice and rats
*Rat flea
*Rat (zodiac)
*Rat-baiting
*Rat-catcher

Further reading

*Barnett, S. Anthony (2002) "The Story of Rats: Their Impact on Us, and Our Impact on Them", Allen & Unwin, Crows Nest, NSW, 202 pages, ISBN 1-86508-519-7 .
*Hendrickson, R. (1983) "More Cunning than Man: A Complete History of the Rat and its Role in Civilization", Kensington Books. ISBN 1-57566-393-7
*Jahn, G. C., P. Cox, S. Mak, and N. Chhorn (1999) "Farmer participatory research on rat management in Cambodia", In G. Singleton, L. Hinds, H. Leirs and Zhibin Zhang [Eds.] "Ecologically-based rodent managemen" ACIAR, Canberra. Ch. 17, pp. 358-371. ISBN 1 86320 262 5
*Leung LKP, Peter G. Cox, G. C. Jahn and Robert Nugent (2002) "Evaluating rodent management with Cambodian rice farmers", "Cambodian Journal of Agriculture" Vol. 5, pp. 21-26.
* [http://www.gutenberg.org/files/17243/17243-h/17243-h.htm#startoftext Matthews, I. (1898) 1st ed. "Full Revelations of a Professional Rat-Catcher, after 25 Years’ Experience", Manchester: Friendly Societies Printing Co. ISBN 1-905124-64-3]
*Musser, G. G. and M. D. Carleton. 1993. "Family Muridae" in D. E. Wilson and D. M. Reeder eds. "Mammal Species of the World a Taxonomic and Geographic Reference", Smithsonian Institution Press, Washington D.C.Pp. 501-755
*Nowak, R. M. (1999) "Walker's Mammals of the World" Vol. 2. Johns Hopkins University Press, London.
*Sullivan, Robert (2004) "Rats: A Year with New York´s Most Unwanted Inhabitants", Granta Books, London.
*Sullivan, Robert (2005) "Rats: Observations on the History and Habitat of the City's Most Unwanted Inhabitants" Bloomsbury USA. ISBN 1-58234-477-9

References and notes

External links

* [http://brainmaps.org/index.php?p=speciesdata&species=rattus-norvegicus High-Resolution Images of the Rat Brain]
* [http://www.anim.med.kyoto-u.ac.jp/nbr/home.htm National Bio Resource Project for the Rat in Japan]
* [http://www.ratbehavior.org/rats.html Rat Behaviour and Biology]
* [http://rgd.mcw.edu/ Rat Genome Database]
* [http://www.the-rag.com/rtgup.html Rats: The Great Underrated Pet]