Rat

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This is an article about wild rats. For pet rats, see Fancy rat. For other uses, see Rat (disambiguation).

{{Taxobox | color = pink | name = Rats | fossil_range = Early Pleistocene - Recent | image = Blackrat.jpg | image_width = 200px | image_caption = Black Rat (Rattus rattus) | 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
*Several subfamilies of Muroids
include animals called rats. }} A rat is any one of about 56 different species of small, nearly omnivorous rodents belonging to the genus Rattus.

1 Rats in culture
2 See also
3 Taxonomy of Rattus
- 3.1 Species of rats
4 Further reading and references
5 External links

The most well-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 of their relatives, the Old World mice, but seldom weigh over 500 grams in the wild. The common 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 a number of others. Other rats such as the Bandicoot rat Bandicota bengalensis are murine rodents related to the true rats, but are not members of the genus Rattus. The widely distributed and problematic commensal species of rats represent 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 Angelo Rantac, black, or Polynesian rats.

In Western countries, many people keep domesticated rats as pets. These are of the species Rattus 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 may be called "fancy rats." But they are still 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.

Rats have a significant impact on food production. Estimates vary, but it is likely that anything between 1/5 and 1/3 of the world's total food output is eaten, spoiled or destroyed by rats and other rodents.

Image:Rattus norvegicus 1.jpg

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 rat flea Xenopsylla cheopis which preyed on Rattus rattus living in European cities of the day; it is notable that these rats were also victims themselves. It should perhaps also be noted that it has recently been suggested that neither rats nor infected fleas would have spread fast enough through Europe to have been a likely culprit. Regardless, rats are frequently blamed for damaging food supplies and other goods. Their reputation has carried into common parlance: in the English language, "rat" is an insult and "to rat on someone" is to betray them by denouncing a crime or misdeed they committed to the authorities. 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. Wild rats living in good environments are typically healthy and robust animals. Wild rats living in cities may suffer themselves from poor diet and internal parasites but do not largely spread disease to humans.

The rat makes a fine pet, known for its intelligence, playfulness and sociality. They are extremely clean. Rats can be taught entertaining tricks, as many other domesticated animals. As with any pet, it is best to seek a rat from a professional breeder rather than a pet store.

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Rats in culture

In imperial Chinese culture, the rat (sometimes referred to as a mouse) is the first of the twelve animals of the Chinese zodiac. Consequently every twelfth year is known as a "year of the rat" in the Chinese calendar. People born in such years are expected to possess qualities associated with rats. These include creativity, honesty, generosity, ambition, a quick temper and wastefulness. "Rats" (i.e. 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."

Image:Ganesha on mouse.jpg In India in the northwestern city of Deshnoke, the Karni Mata Temple (the Indo-European roots of Mata traceable to the modern english 'mother') in reverence of an incarnation of Durga, the Goddess of War is devoted to the worship of rats. The holy animals are called "Kabbas" and many people undertake pilgrimage from afar to see these animals. It is believed the rats will be reincarnated into their next lives as Sadhus, Hindu holy men. The attending priests feed milk and grain to the animals of which also the pilgrims partake. Eating food that has been touched by the animals is considered a blessing.

In Hindu mythology a rat is the vehicle of Lord Ganesh.

Western associations with the rat are generally negative. For instance, "Rats!" is used as a substitute for various vulgar interjections. These associations do not draw, per se, from any biological or behavioral trait of the rat, but possibly from the debated historical association of the rat with the medieval Black Death. Rats are seen, some would say unfairly, as vicious, unclean, parasitic animals that steal food and spread disease. In one particularly infamous example, ravenous rats are used as a torture device in the novel Nineteen Eighty-Four, and in the movie 2 Fast 2 Furious. The H. P. Lovecraft story "The Rats in the Walls" also deals with rats in a less than flattering manner. When anthropomorphized, rats are usually depicted as selfish, crude and untrustworthy, with the characters of The Secret of NIMH, Ratz and Terry Pratchett's The Amazing Maurice and his Educated Rodents being the major exceptions. Describing a person as "rat-like" usually implies they are unattractive and suspicious. By contrast, mice are stereotyped as cute and bourgeois.

On the Isle of Man the word 'rat' should be used with caution; even today many people may be shocked, and indeed offended upon its utterance. It is considered bad luck to mention this word. The origins of this superstition date far back, possibly to a time when many Manx people lived off the sea, where it was a sign of trouble when the rats were leaving the ship. Local alternatives include longtail, joey, queerfella, ringie and the Manx word, roddan. In recent times, many young people have converted to saying "r-a-t", owing to the influence of British immigrants.

Because of the negative cultural associations with the species, rats are often used in scientific experiments that may damage the animal; many animal rights activists allege that treatment of rats in this context is extremely cruel. The term "lab rat" is sometimes used, therefore (like guinea pig) to describe a person who is manipulated in a social experiment.

More recently, rat has become a criminal slang term for a police informant; in this context, it is used as both a noun and a verb.

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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. These are: 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: