Encyclopedia
A
rat is any one of about 56 different species of small,
omnivorous rodents belonging to the genus
Rattus.
The Rat
The best-known rat species are the
Black Rat Rattus rattus and the
Brown Rat R. 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
brown,
black, or Polynesian rats.
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 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.
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
R. rattus living in European cities of the day; it is notable that these rats were victims of the plague themselves. It has recently been suggested that neither rats nor infected fleas would have spread fast enough through Europe to be a likely culprit, although this is controversial and research continues. 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 to the authorities a crime or misdeed they committed. While modern wild rats can carry
Leptospirosis and some other "zoonotic" conditions , 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 generally spread disease to humans.
The rat makes a fine pet, known for its intelligence, playfulness and sociability. They are extremely clean. Rats can be taught entertaining tricks, in the same way as many other domesticated animals. It has been observed that Rats can actually last longer without water than Camels.
Rats have a normal lifespan ranging from two to five years, though three years is typical.
Rats in culture
Ancient Romans did not generally differentiate between rats and mice, instead referring to the former as Mus Maximus and the latter as Mus Minimus .
In Imperial
Chinese culture, the rat is the first of the twelve animals of the Chinese zodiac. People born in this year are expected to possess qualities associated with rats. These include creativity, honesty, generosity, ambition, a quick temper and wastefulness. "Rats" are said to get along well with "monkeys" and "dragons," and to get along poorly with "horses."
In
India in the northwestern city of Deshnoke, the Karni Mata Temple, the rats are held to be destined for
reincarnation as
Sadhus,
Hindu holy men. The attending priests feed milk and grain, of which the pilgrims also partake, to the animals. Eating food that has been touched by the animals is considered a blessing from god. In
Hindu mythology, a rat is the vehicle of
Ganesha.
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 association of rats with the 14th-century medieval plague called the
Black Death. Rats are seen as vicious, unclean, parasitic animals that steal food and spread disease. While undomesticated rats, dogs, and cats may all be pests in urban areas, in Western countries poisoning rats is commonly accepted, while doing the same to feral dogs and cats would be an unpopular solution in the view of many people. 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 is a dystopian [i] novel [i] written by the English [i] ...
by
George Orwell'. Rats are the most common enemy in
Brian Jacques's
Redwall series of anthropomorphic fantasy novels. There are obvious exceptions; for example, the characters of
Mrs. Frisby and the Rats of NIMH is a children's book [i] by Robert C. O'Brien [i], illustrated by Zena Bernstein [i] ...
, the television series
Ratz and
Terry Pratchett's
The Amazing Maurice and his Educated Rodents. Describing a person as "rat-like" usually implies he is unattractive and suspicious. In contrast, mice are stereotyped as cute and bourgeois.
On the
Isle of Man there is a taboo against the word "rat." See longtail for more information.
Rat is also a term in criminal slang for a criminal informant.
Rats are often used in destructive scientific
experiments; many
animal rights activists allege that treatment of rats in this context is cruel. The term "lab rat" is therefore sometimes used, like
guinea pig, to describe a person who is manipulated in a social experiment.
Rats as vermin
By most standards, rats are considered pests or vermin. They can be very destructive to crops and property. Rats can quickly overpopulate when they live in a place where they have no predators, such as in certain cities, and their numbers can become hard to contain. Because of this, the entire province of
Alberta,
Canada has upheld and maintained a rat-free status since the early 1950s; it is even illegal to keep pet rats.
Rats have a significant impact on food production. Estimates vary, but it is likely that anything between 1/5 and ? of the world's total food output is eaten, spoiled or destroyed by rats and other rodents.,
Rats can carry over thirty different diseases dangerous to humans, including
Weil's disease,
typhus and
bubonic plague.
Because they are nocturnal, when rats are seen out and about in the daytime, it can mean that their nesting areas have been disturbed or, more typically, rat activity in the daylight hours means there is overpopulation of them in the local area. It is typically at this point that vermin control measures tend to increase.
Rats often chew electrical cables. Around 26% of all electrical cable breaks are caused by rats, and around 18% of all phone cable breaks. Around 25% of all fires of unknown origin are estimated to be caused by rats.
Rats, particularly roof rats , can enter the attics of homes where they mate and nest. This problem occurs commonly in coastal, temperate climates and affects even the cleanest, well-kept homes.
See also
...
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 natives
- New Guinea natives
- xanthurus group
The following list is alphabetical.
Species 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 hoffmani
- 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 sanila
- 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
Further reading and references
- The Story of Rats: Their Impact on Us, and Our Impact on Them, S. Anthony Barnett, Allen & Unwin, Crows Nest, NSW, Australia, 2002, trade paperback, 202 pages, ISBN 1-86508-519-7 .
- Matthews, I. 1st ed. Manchester: Friendly Societies Printing Co. ISBN 1-905124-64-3
- Musser, G. G. and M. D. Carleton. 1993. Family Muridae. Pp. 501-755 in Mammal Species of the World a Taxonomic and Geographic Reference. D. E. Wilson and D. M. Reeder eds. Smithsonian Institution Press, Washington D.C.
- Nowak, R. M. 1999. Walker's Mammals of the World, Vol. 2. Johns Hopkins University Press, London.
- Sullivan, R. 2004. Rats A Year with New York´s Most Unwanted Inhapitants. Granta Books, London
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