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Temporal range: Early Pleistocene – Recent
Rattus norvegicus 1.jpg
The common brown rat (Rattus norvegicus).
Scientific classification
Fischer de Waldheim, 1803

64 species


Stenomys Thomas, 1910

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This article is about the genus Rattus. For pet rats, see Fancy rat. For other uses, see Rat (disambiguation).
Temporal range: Early Pleistocene – Recent
Rattus norvegicus 1.jpg
The common brown rat (Rattus norvegicus).
Scientific classification
Fischer de Waldheim, 1803

64 species


Stenomys Thomas, 1910



Species and description



A rat in a city street
Idol of a rat in Patan (Nepal)


Wild rodents, including rats, can carry many different zoonotic pathogens, such as Leptospira, Toxoplasma gondii, and Campylobacter.[2] The Black Death is traditionally believed to have been caused by the micro-organism Yersinia pestis, carried by the tropical rat flea (Xenopsylla cheopis) which preyed on black rats living in European cities during the epidemic outbreaks of the Middle Ages; these rats were used as transport hosts. Other zoonotic diseases linked to pest rodents include classical swine fever and foot-and-mouth disease.




Main article: Fancy rat

Specially bred rats have been kept as pets at least since the late 19th century. Pet rats are typically variants of the species brown rat, but black rats and giant pouched rats are also known to be kept. Pet rats behave differently from their wild counterparts depending on how many generations they have been kept as pets.[3] Pet rats do not pose any more of a health risk than pets such as cats or dogs.[4] Tamed rats are generally friendly and can be taught to perform selected behaviors.

Subjects for scientific research

Main article: Laboratory rat
A laboratory rat strain, known as a Zucker rat, is bred to be genetically prone to diabetes, the same metabolic disorder found among humans.





A rat in a suburb of Vancouver

Because of the ability to learn, rats were early on investigated to see whether they may exhibit general intelligence, expressed by the presence of a g factor, like larger or more complex animals. A 1929 study did not find a g factor,[9] nor did a 1990 work;[10] a 1935 study[11] did:

Robert Thorndike, for example, provided strong evidence for g in rats by the use of a variety of tests such as mazes, problem-solving tasks, and simple avoidance conditioning (Thorndike 1935). Performances tended to correlate across tasks, with stronger associations found between mazes and problem-solving than with simple avoidance tasks. Thorndike (1935) also reviewed a dozen earlier studies which also suggested that the highest correlations are found between more complex problem-solving tasks. However, it should be noted that there were other contemporary studies that found split or near zero-order correlation matrices for other populations of rats across cognitive batteries (see Royce 1950).


In 1993, Anderson measured rat performance and factor analysis produced a g, and also correlations with rat brain size[13] (as in humans and primates). Locurto & Scanlon 1998,[14] Matzel et al. 2003,[15] Matzel et al. 2004,[16] Kolata et al. 2009[17] and Matzel et al. 2011[18] replicated the factor (but did not investigate brain size); 2003 Locurto et al., 2006 Locurto et al. in contrast found their factor analysis giving 4 factors rather than 1.

Social intelligence



Rat meat dishes in Yangshuo, Guangxi, China

Rat meat is a food that, while taboo[20][21] in some cultures, is a dietary staple in others. Taboos include fears of disease or religious prohibition, but in many places, the high number of rats has led to their incorporation into the local diets.

In some cultures, rats are or have been limited as an acceptable form of food to a particular social or economic class. In the Mishmi culture of India, rats are essential to the traditional diet, as Mishmi women may eat no meat except fish, pork, wild birds and rats.[22] Conversely, the Musahar community in north India has commercialised rat farming as an exotic delicacy.[23] In the traditional cultures of the Hawaiians and the Polynesians, rat was an everyday food for commoners. When feasting, the Polynesian people of Rapa Nui could eat rat meat, but the king was not allowed to, due to the islanders' belief in his "state of sacredness" called tapu.[24] In studying precontact archaeological sites in Hawaii, archaeologists have found the concentration of the remains of rats associated with commoner households accounted 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 the rats were eaten as food. The greater occurrence of rat remains associated with commoner households may indicate the elites of precontact Hawaii did not consume them as a matter of status or taste.[25]

Bandicoot rats are an important food source among some peoples in Southeast Asia, and the United Nations Food and Agriculture Organization estimated rat meat makes up half the locally produced meat consumed in Ghana, where cane rats are farmed and hunted for their meat. African slaves in the American South were known to hunt wood rats (among other animals) to supplement their food rations,[26] and Aborigines along the coast in southern Queensland, Australia, regularly included rats in their diet.[27]



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 are available to individual snake owners, as well as to large reptile zoos, from many suppliers. In Britain, the government in 2007 ruled out the feeding of any live mammal to another animal. The rule says the animal must be dead (frozen) then given to the animal to eat. The rule was put into place mainly because of the pressure of the RSPCA and people who found it cruel.


Rats can serve as zoonotic vectors for certain pathogens and thus cause disease, such as Lassa fever, leptospirosis and Hantavirus infection.

Odor detection


Rats as pests

Rats have long been considered deadly pests. Once considered a modern myth, the rat flood in India has now been verified. Indeed every fifty years, armies of bamboo rats descend upon rural areas and devour everything in their path.[32] Rats have long been held up as the chief villain in the spread of the Bubonic Plague,[33] however recent studies show that they alone could not account for the rapid spread of the disease through Europe in the Middle Ages.[34] Still, the Center for Disease Control does list nearly a dozen diseases [35] directly linked to rats. Most urban areas battle rat infestations. Rats in New York City are famous for their size and prevalence. The urban legend that the rat population in Manhattan equals that of its human population (a myth definitively refuted by Robert Sullivan in his book "Rats") speaks volumes about New Yorkers' awareness of the presence, and on occasion boldness and cleverness, of the rodents.[36] New York has specific regulations for getting rid of rats—multi-family residences and commercial businesses must use a specially trained and licensed exterminator.[37] Places to look for rat infestations are around pipes, behind walls and near garbage cans. Effective rat control requires municipal workers and individuals to work together.

Rats as invasive species

When introduced into locations where rats previously did not exist they cause a huge amount of environmental degradation. Rattus rattus, the black rat, is considered to be one of the world's worst invasive species.[38]

As part of island restoration some islands have had their rat populations eradicated to protect or restore the ecology. Hawadax Island, Alaska was declared rat free after 229 years and Campbell Island, New Zealand after almost 200 years. Breaksea Island in New Zealand was declared rat free in 1988 after an eradication campaign based on a successful trial on the smaller Hawea Island nearby.

The Canadian province of Alberta is notable for its history of being free of the Norwegian rat. A rat control program was created after they started making inroads there during World War II. The program still actively employs patrols along its border with Saskatchewan.



On the Isle of Man (a dependency of the British Crown), there is a taboo against the word "rat".[citation needed]

Asian cultures

Main article: Rat (zodiac)


The indigenous rats are allowed to run freely throughout the Karni Mata Temple.


European cultures








Depictions of rats in fiction are historically inaccurate and negative. The most common falsehood is the squeaking almost always heard in otherwise realistic portrayals (i.e. nonanthropomorphic). While the recordings may be of actual squeaking rats, the noise is uncommon - they may do so only if distressed, hurt, or annoyed. Normal vocalizations are very high-pitched, well outside the range of human hearing. Rats are also often cast in vicious and aggressive roles when in fact, their shyness helps keep them undiscovered for so long in an infested home.

The actual portrayals of rats vary from negative to positive with a majority in the negative and ambiguous.[40] The rat plays a villain in several mouse societies; from Brian Jacques's Redwall and Robin Jarvis's The Deptford Mice, to the roles of Disney's Professor Ratigan and Kate DiCamillo's Roscuro and Botticelli. They have often been used as a mechanism in horror; being the titular evil in stories like The Rats or H.P. Lovecraft's The Rats in the Walls [40] and in films like Willard and Ben. Another terrifying use of rats is as a method of torture, for instance in Room 101 in George Orwell's Nineteen Eighty-Four or The Pit and the Pendulum by Edgar Allan Poe.

Selfish helpfulness —those willing to help for a price— has also been attributed to fictional rats.[40] Templeton, from E. B. White's Charlotte's Web, repeatedly reminds the other characters that he is only involved because it means more food for him, and the cellar-rat of John Masefield's The Midnight Folk requires bribery to be of any assistance.


Some fictional works use rats as the main characters. Notable examples include the society created by O'Brien's Mrs. Frisby and the Rats of NIMH, Doctor Rat, Rizzo the Rat from The Muppets, and animated films such as Pixar's Ratatouille. Mon oncle d'Amérique ("My American Uncle"), a 1980 French film, illustrates Henri Laborit's theories on evolutionary psychology and human behaviors by using short sequences in the storyline showing lab rat experiments.


The Pied Piper

Main article: Pied Piper of Hamelin

One of the oldest and most historic stories about rats is The Pied Piper of Hamelin, in which a rat-catcher leads away an infestation with enchanted music—the piper is later refused payment, so he in turn leads away the town's children. This tale, placed in Germany around the late 13th century, has inspired the realms of film, theatre, literature, and even opera. The subject of much research, some theories have intertwined the tale with events related to the Black Plague, in which black rats may have played an important role. Fictional works based on the tale that focus heavily on the rat aspect include Pratchett's The Amazing Maurice and his Educated Rodents, and Belgian graphic novel Le Bal du Rat Mort (The Ball of the Dead Rat).

Taxonomy of Rattus




Genus Rattus - Typical rats

See also


  1. ^ Meerburg BG, Singleton GR, Leirs H (2009). "The Year of the Rat ends: time to fight hunger!". Pest Manag Sci 65 (4): 351–2. doi:10.1002/ps.1718. PMID 19206089. 
  3. ^ "Wild Rats in Captivity and Domestic Rats in the Wild". Ratbehaviour.org. Retrieved 2009-07-04. 
  4. ^ "Merk Veterinary Manual Global Zoonoses Table". Merckvetmanual.com. Retrieved 2006-11-24. 
  6. ^ "Rats Capable Of Reflecting On Mental Processes". Sciencedaily.com. 2007-03-09. Retrieved 2012-09-24. 
  7. ^ Gibbs RA et al: Genome sequence of the Brown Norway rat yields insights into mammalian evolution.: Nature. 2004 April 1; 428(6982):475-6.
  8. ^ "Genome project". www.ensembl.org. Retrieved 17 February 2007. 
  11. ^ Thorndike, R., "Organization of behavior in the albino rat", Genet. Psychol. Monogr., 17 (1935) 1-70
  12. ^ quote from 2002 Galsworthy et al "Evidence for general cognitive ability (g) in heterogeneous stock mice and an analysis of potential confounds"
  13. ^ 1993 Anderson, "Evidence from the rat for a general factor that underlies cognitive performance and that relates to brain size: intelligence?"

    "The data on a group of 22 rats, each measured for their speed of reasoning, accuracy of reasoning, response flexibility, and attention for novelty, were subjected to two different methods of factor analysis. By both methods, the correlation matrix of their performance was consistent with a single-factor model. In a second cohort of rats, where brain size was known, the score for this ‘general factor’ was computed. The regression for brain weight and the general factor was significant."

  14. ^ "Individual differences and a spatial learning factor in two strains of mice (Mus musculus)"
  15. ^ "Individual Differences in the Expression of a "General" Learning Ability in Mice". Neuro.cjb.net. Retrieved 2012-09-24. [dead link]
  16. ^ "Novelty-Seeking in Outbred Mice Covaries with General Learning Abilities Irrespective of Stress Reactivity, Emotionality, and Physical Attributes" (PDF). Ruccs.rutgers.edu. Retrieved 2012-09-24. [dead link]
  17. ^ USA (2012-05-24). "Domain-Specific and Domain-General Learning Factors are Expressed in Genetically Heterogeneous CD-1 mice". Ncbi.nlm.nih.gov. Retrieved 2012-09-24. 
  18. ^ "Individual Differences in Animal Intelligence: Learning, Reasoning, Selective Attention and Inter-Species Conservation of a Cognitive Trait" (PDF). Retrieved 2012-09-24. [dead link]
  19. ^ "Rats free each other from cages". Nature.com. Retrieved 2012-09-24. 
  20. ^ Newvision Archive (2005-03-10). "Rats for dinner, a delicacy to some, a taboo to many". Newvision.co.ug. Retrieved 2012-09-24. 
  21. ^ "Rat meat taboo". News.google.com. Retrieved 2012-09-24. 
  22. ^ Mills, J. P. (January 1952) The Mishmis of the Lohit Valley, Assam. The Journal of the Royal Anthropological Institute of Great Britain and Ireland, Vol. 82, No. 1. pp. 1-12
  23. ^ Musahar Hindus commercialise rat farming[dead link]
  24. ^ Leach, Helen. (February 2003) Did East Polynesians Have a Concept of Luxury Foods? World Archaeology, Vol. 34, No. 3, Luxury Foods. pp. 442-457.
  25. ^ 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
  26. ^ 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
  27. ^ Hobson, Keith A.; Stephen Collier. (April 1984) Marine and Terrestrial Protein in Australian Aboriginal Diets. Current Anthropology, Vol. 25, No. 2. pp. 238-240
  28. ^ Manuel Vázquez Montalbán, La cocina de los mediterráneos, Ediciones B - Mexico
  29. ^ 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.
  31. ^ "Video of Bart Weetjens talk on use of rats as odour detectors". Ted.com. Retrieved 2012-09-24. 
  32. ^ "Massive plagues of rats swarm across India every fifty years". Io9.com. Retrieved 2013-03-15. 
  33. ^ "The Black Plague". Unc.edu. Retrieved 2013-03-15. 
  34. ^ Maev Kennedy (2011-08-17). "Black Death study lets rats off the hook | World news". London: The Guardian. Retrieved 2013-03-15. 
  35. ^ "CDC - Diseases directly transmitted by rodents - Rodents". Cdc.gov. 2011-06-07. Retrieved 2013-03-15. 
  36. ^ "Sean Wilsey reviews ‘Rats’ by Robert Sullivan · LRB 17 March 2005". Lrb.co.uk. Retrieved 2013-03-15. 
  37. ^ [1][dead link]
  38. ^ "100 of the World's Worst Invasive Alien Species". Global Invasive Species Database. Retrieved 17 February 2013. 
  39. ^ "Nevada Journal: Louts and the Rat World". Nj.npri.org. Retrieved 2012-09-24. 
  40. ^ a b c Clute, John; John Grant (March 15, 1999). The Encyclopedia of Fantasy. St. Martin's Griffin. p. 642. ISBN 0-312-19869-8. 

Further reading

External links