Rat Varieties Rats In The Laboratory Rats In Culture

The term rat is also used in the names of other small mammals which are not true rats. Examples include the wood or pack rat, a number of species loosely called kangaroo rats and the Mole Rat , Bandicota bengalensis.

In Western countries, many people keep domestic rats as pets. Descendants of Norwegian rats bred for research, these animals are often called " fancy rats", "coloured rats" or "colour rats." Domesticated rats tend to be both more docile than their wild ancestors and more disease prone, presumably due to inbreeding.

1 Varieties

There are over 50 species of rats, the most well-known of which are the Brown RatThe Brown Rat Rattus norvegicus is one of the most well-known and common rats, and also one of the largest. Thought to have originated in northern China, this rodent has now spread to all continents and is the dominant rat in Europe and much of North Amer, Rattus norvegicus; the Black Rat, Rattus rattus; the Polynesian Rat , Rattus exulans.

These three common species often live with and near humanHuman beings are defined variously in biological, spiritual, and cultural terms, or in combinations thereof. Biologically, they are classified as Homo sapiens ( Latin for knowing man , a primate species of mammal with a highly developed brain. In spirituas, share their food and spread diseaseA disease is any abnormal condition of the body or mind that causes discomfort, dysfunction, or distress to the person affected or those in contact with the person. Sometimes the term is used broadly to include injuries, disabilities, syndromes, symptoms,. At least one of these three species occurs on over 80% of island groups around the world and they have caused about half of bird and reptile extinctions. The Black Plague is believed to have been spread by rat-borne parasites. Rats are also blamed for damaging food supplies and other goods. They have a very poor reputation; in the English languageThe English language is a West Germanic language, originating from England. It is the third most common "first" language (native speakers), with around 402 million people in 2002. English has lingua franca status in many parts of the world, due to the mil, "rat" is an insult and "to rat on someone" is to betray them by denouncing a crime or misdeed they committed to the authorities.

Rats might eat each other in stressful environments or when the number of rats in a space is very high, but cannibalism to prevent diseases from spreading is normal, where dead rats are eaten before they start spreading diseases.

2 Rats in the laboratory

Like mice, rats (especially albino Rattus norvegicus) are frequently subjects of medical, psychological and other biological experiments due to their rapid growth to sexual maturity and because rats are easily kept and bred in captivity. Scientists have bred many strains or " lines" of rats specifically for experimentation. Generally, these lines are not transgenic, however, because the easy techniques of genetic transformation that work in mice do not work in rats. This has frustrated many investigators, who regard many aspects of behavior and physiology in rats as more relevant to humans and easier to observe than in mice, but who wish to trace their observations to underlying genes. As a result, many researchers have been forced to study questions in mice that might be better pursued in rats. In October 2003, however, researchers succeeded in cloning two laboratory rats by the problematic technique of nuclear transfer. This may lead to more rats being used as genetic research subjects.

3 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."

The stereotypes associated with rats in Western civilization are less complimentary. Rats are seen as vicious, unclean, parasitic animals that steal food and spread disease. When anthropomorphized, rats are usually depicted as selfish, crude and untrustworthy, with the characters of The Secret of NIMH being the major exception. Describing a person as ratlike usually implies they are unattractive and suspicious. By contrast, mice are sterotyped as cute and bourgeois.

3.1 See also

Rat (Ned's Atomic Dustbin) , a band member of Ned's Atomic Dustbin
Rat (zodiac)
Fear Factor
Rat Park

4 Further reading

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, BooksEnthsiast.com.

5 See also

List of fictional mice and rats

6 External links

Rat Genome Database

Rats

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