62-592: 68 species Rattus is a genus of muroid rodents , all typically called rats . However, the term rat can also be applied to rodent species outside of this genus. The best-known Rattus species are the black rat ( R. 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 Old World mice , which are their relatives, but seldom weigh over 500 grams (1.1 lb) in
124-456: A muroid rodent is discovered, its common name includes the term mouse if it is smaller, or rat if it is larger. The common terms rat and mouse are not taxonomically specific. Typical mice are classified in the genus Mus , but the term mouse is not confined to members of Mus and can also apply to species from other genera such as the deer mouse ( Peromyscus ) . Domestic mice sold as pets often differ substantially in size from
186-509: A deterrent simply by their presence. Rats have the ability to swim up sewer pipes into toilets. Rats will infest any area that provides shelter and easy access to sources of food and water, including under sinks, near garbage, and inside walls or cabinets. Rats can serve as zoonotic vectors for certain pathogens and thus spread disease, such as bubonic plague , Lassa fever , leptospirosis , and Hantavirus infection. Researchers studying New York City wastewater have also cited rats as
248-594: A dozen diseases directly linked to rats. Most urban areas battle rat infestations. A 2015 study by the American Housing Survey (AHS) found that eighteen percent of homes in Philadelphia showed evidence of rodents. Boston , New York City , and Washington, D.C. , also demonstrated significant rodent infestations. Indeed, rats in New York City are famous for their size and prevalence. The urban legend that
310-465: A keen sense of hearing. They depend on their sense of smell to locate food and avoid predators. In the wild, mice are known to build intricate burrows. These burrows have long entrances and are equipped with escape tunnels. In at least one species, the architectural design of a burrow is a genetic trait. The most common mice are murines , in the same clade as common rats . They are murids, along with gerbils and other close relatives. Researchers at
372-769: A large variety of vegetables. Despite popular belief, most mice do not have a special appetite for cheese. They will only eat cheese for lack of better options. Mice are common experimental animals in laboratory research of biology and psychology fields primarily because they are mammals , and also because they share a high degree of homology with humans. They are the most commonly used mammalian model organism , more common than rats . The mouse genome has been sequenced, and virtually all mouse genes have human homologs . The mouse has approximately 2.7 billion base pairs and 20 pairs of chromosomes. They can also be manipulated in ways that are illegal with humans, although animal rights activists often object. A knockout mouse
434-523: A minimum. The effectiveness has been aided by a similar but newer program in Saskatchewan which prevents rats from even reaching the Alberta border. Alberta still employs an armed rat patrol to control rats along Alberta's borders. About ten single rats are found and killed per year, and occasionally a large localized infestation has to be dug out with heavy machinery, but the number of permanent rat infestations
496-645: A modern myth, the rat flood in India occurs every fifty years, as armies of bamboo rats descend upon rural areas and devour everything in their path. Rats have long been held up as the chief villain in the spread of the Bubonic Plague ; however, recent studies show that rats alone could not account for the rapid spread of the disease through Europe in the Middle Ages . Still, the Centers for Disease Control does list nearly
558-445: A new area, they quickly reproduce to take advantage of the new food supply. In particular, they prey on the eggs and young of forest birds, which on isolated islands often have no other predators and thus have no fear of predators . Some experts believe that rats are to blame for between forty percent and sixty percent of all seabird and reptile extinctions, with ninety percent of those occurring on islands. Thus man has indirectly caused
620-598: A popular choice due to their high intelligence, ingenuity, aggressiveness , and adaptability . Their psychology seems in many ways similar to that of humans. Inspired by B.F. Skinner ’s famous box which dispensed food pellets when rats pushed a lever, photographer Augustin Lignier gave two rats periodic, unpredictable rewards for pressing a button. He likened their repeated button-pressing behaviors to people’s fascinations with digital and social media. Early studies found evidence both for and against measurable intelligence using
682-458: A province in 1905. Black rats cannot survive in its climate at all, and brown rats must live near people and in their structures to survive the winters. There are numerous predators in Canada's vast natural areas which will eat non-native rats, so it took until 1950 for invading rats to make their way over land from Eastern Canada. Immediately upon their arrival at the eastern border with Saskatchewan ,
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#1732891420105744-548: 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 seen as the vehicle of Ganesha , 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
806-481: A relatively short time. Mice are generally very docile if raised from birth and given sufficient human contact. However, certain strains have been known to be quite temperamental. Many people buy mice as companion pets. They can be playful, loving and can grow used to being handled. Like pet rats, pet mice should not be left unsupervised outside as they have many natural predators, including (but not limited to) birds, snakes, lizards, cats, and dogs. Male mice tend to have
868-410: A state of proprioceptive balance in its environment. Further mechanobiological investigations of the constituent tendons in the tail of the rat have identified multiple factors that influence how the organism navigates its environment with this structure. A particular example is that of a study in which the morphology of these tendons is explicated in detail. Namely, cell viability tests of tendons of
930-524: A stronger odor than the females. However, mice are careful groomers and as pets they never need bathing. Well looked-after mice can make ideal pets. Some common mouse care products are: Mice are a staple in the diet of many small carnivores . In various countries mice are used as feed for pets such as snakes , lizards , frogs , tarantulas , and birds of prey , and many pet stores carry mice for this purpose. Such mice are sold in various sizes and with various amounts of fur. Mice without fur are easier for
992-624: A successful trial on the smaller Hawea Island nearby. In January 2015, an international "Rat Team" set sail from the Falkland Islands for the British Overseas Territory of South Georgia and the South Sandwich Islands on board a ship carrying three helicopters and 100 tons of rat poison with the objective of "reclaiming the island for its seabirds". Rats have wiped out more than 90% of the seabirds on South Georgia, and
1054-415: A thermoregulation function that follows from its anatomical construction. This particular tail morphology is evident across the family Muridae, in contrast to the bushier tails of Sciuridae , the squirrel family. The tail is hairless and thin skinned but highly vascularized, thus allowing for efficient countercurrent heat exchange with the environment. The high muscular and connective tissue densities of
1116-428: A unique defense mechanism known as degloving in which the outer layer of the integument can be detached in order to facilitate the animal's escape from a predator. This evolutionary selective pressure has persisted despite a multitude of pathologies that can manifest upon shedding part of the tail and exposing more interior elements to the environment. Paramount among these are bacterial and viral infection, as
1178-494: Is a genetically modified mouse that has had one or more of its genes made inoperable through a gene knockout . Experimental mouse model systems include mouse models of colorectal and intestinal cancer , mouse models of Down syndrome and mouse models of breast cancer metastasis . Reasons for common selection of mice are that they are small and inexpensive, have a widely varied diet, are easily maintained, and can reproduce quickly. Several generations of mice can be observed in
1240-459: Is notable for being the largest inhabited area on Earth which is free of true rats due to very aggressive government rat control policies. It has large numbers of native pack rats , also called bushy-tailed wood rats, but they are forest-dwelling vegetarians which are much less destructive than true rats. Alberta was settled by Europeans relatively late in North American history and only became
1302-475: Is referred to as a mischief . The common species are opportunistic survivors and often live with and near humans ; therefore, they are known as commensals . They may cause substantial food losses, especially in developing countries. However, the widely distributed and problematic commensal species of rats are a minority in this diverse genus. Many species of rats are island endemics , some of which have become endangered due to habitat loss or competition with
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#17328914201051364-478: Is subject to special measures and regularly monitored for rat invasions. As part of island restoration , some islands' rat populations have been 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
1426-612: Is zero. 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 , there is a taboo against the word " rat ". 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, intelligence, honesty, generosity, ambition,
1488-506: The "g factor" in rats. Part of the difficulty of understanding animal cognition , generally, is determining what to measure. One aspect of intelligence is the ability to learn, which can be measured using a maze like the T-maze . Experiments done in the 1920s showed that some rats performed better than others in maze tests, and if these rats were selectively bred, their offspring also performed better, suggesting that in rats an ability to learn
1550-566: The aortic branches . Aortic arches studied in rats exhibit abnormalities similar to those of humans, including altered pulmonary arteries and double or absent aortic arches. Despite existing anatomical analogy in the inthrathoracic position of the heart itself, the murine model of the heart and its structures remains a valuable tool for studies of human cardiovascular conditions. The rat's larynx has been used in experimentations that involve inhalation toxicity, allograft rejection, and irradiation responses. One experiment described four features of
1612-415: The brown rat or wharf rat , has also been carried worldwide by ships in recent centuries. The ship or wharf rat has contributed to the extinction of many species of wildlife, including birds, small mammals, reptiles, invertebrates, and plants, especially on islands. True rats are omnivorous , capable of eating a wide range of plant and animal foods, and have a very high birth rate . When introduced to
1674-582: The common name of a large muroid rodent will include the word "rat", while a smaller muroid's name will include "mouse". The common terms rat and mouse are not taxonomically specific. There are 56 known species of rats in the world. The best-known rat species are the black rat ( Rattus rattus ) and the brown rat ( Rattus norvegicus ). This group, generally known as the Old World rats or true rats, originated in Asia . Rats are bigger than most Old World mice , which are their relatives, but seldom weigh over 500 grams ( 17 + 1 ⁄ 2 oz) in
1736-520: The Alberta government implemented an extremely aggressive rat control program to stop them from advancing further. A systematic detection and eradication system was used throughout a control zone about 600 kilometres (400 mi) long and 30 kilometres (20 mi) wide along the eastern border to eliminate rat infestations before the rats could spread further into the province. Shotguns, bulldozers, high explosives, poison gas, and incendiaries were used to destroy rats. Numerous farm buildings were destroyed in
1798-593: The Max Planck Institute of Neurobiology have confirmed that mice have a range of facial expressions. They used machine vision to spot familiar human emotions like pleasure, disgust, nausea, pain, and fear. In nature, mice are largely herbivores , consuming any kind of fruit or grain from plants. However, mice adapt well to urban areas and are known for eating almost all types of food scraps. In captivity, mice are commonly fed commercial pelleted mouse diet. These diets are nutritionally complete, but they still need
1860-500: The animal to consume; however, mice with fur may be more convincing as animal feed. Humans have eaten mice since prehistoric times . In Victorian Britain, fried mice were still given to children as a folk remedy for bed-wetting ; while Jared Diamond reports creamed mice being used in England as a dietary supplement during Second World War rationing. Mice are a delicacy throughout eastern Zambia and northern Malawi , where they are
1922-465: The brown, black, or Polynesian rat . Wild rodents, including rats, can carry many different zoonotic pathogens, such as Leptospira , Toxoplasma gondii , and Campylobacter . The Black Death is traditionally believed to have been caused by the microorganism Yersinia pestis , carried by the tropical rat flea ( Xenopsylla cheopis ), which preyed on black rats living in European cities during
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1984-463: The common house mouse. This is attributable to breeding and different conditions in the wild. The best-known strain of mouse is the white lab mouse . It has more uniform traits that are appropriate to its use in research. Cats , wild dogs , foxes , birds of prey , snakes and certain kinds of arthropods have been known to prey upon mice. Despite this, mice populations remain plentiful. Due to its remarkable adaptability to almost any environment ,
2046-621: The condition is known as rat mite dermatitis . When introduced into locations where rats previously did not exist, they can wreak an enormous degree of environmental degradation . Rattus rattus , the black rat , is considered to be one of the world's worst invasive species. Also known as the ship rat , it has been carried worldwide as a stowaway on seagoing vessels for millennia and has usually accompanied men to any new area visited or settled by human beings by sea. Rats first got to countries such as America and Australia by stowing away on ships. The similar species Rattus norvegicus ,
2108-532: The dumbo rat, a popular pet choice due to their low, saucer-shaped ears. A breeding standard exists for rat fanciers wishing to breed and show their rat at a rat show. In 1895, Clark University in Worcester, Massachusetts , established a population of domestic albino brown rats to study the effects of diet and for other physiological studies. Over the years, rats have been used in many experimental studies, adding to our understanding of genetics , diseases ,
2170-493: The effects of drugs , and other topics that have provided a great benefit for the health and wellbeing of humankind. The aortic arches of the rat are among the most commonly studied in murine models due to marked anatomical homology to the human cardiovascular system . Both rat and human aortic arches exhibit subsequent branching of the brachiocephalic trunk , left common carotid artery , and left subclavian artery , as well as geometrically similar, nonplanar curvature in
2232-427: The epidemic outbreaks of the Middle Ages ; these rats were used as transport hosts. Another zoonotic disease linked to the rat is foot-and-mouth disease . Rats become sexually mature at age 6 weeks, but reach social maturity at about 5 to 6 months of age. The average lifespan of rats varies by species, but many only live about a year due to predation. The black and brown rats diverged from other Old World rats in
2294-676: The extinction of many species by accidentally introducing rats to new areas. Rats are found in nearly all areas of Earth which are inhabited by human beings. The only rat-free continent is Antarctica , which is too cold for rat survival outdoors, and its lack of human habitation does not provide buildings to shelter them from the weather. However, rats have been introduced to many of the islands near Antarctica, and because of their destructive effect on native flora and fauna, efforts to eradicate them are ongoing. In particular, Bird Island (just off rat-infested South Georgia Island ), where breeding seabirds could be badly affected if rats were introduced,
2356-461: The forests of Asia during the beginning of the Pleistocene . The characteristic long tail of most rodents is a feature that has been extensively studied in various rat species models, which suggest three primary functions of this structure: thermoregulation , minor proprioception , and a nocifensive -mediated degloving response. Rodent tails—particularly in rat models—have been implicated with
2418-423: The high density of vascular tissue within the tail becomes exposed upon avulsion or similar injury to the structure. The degloving response is a nocifensive response, meaning that it occurs when the animal is subjected to acute pain , such as when a predator snatches the organism by the tail. Specially bred rats have been kept as pets at least since the late 19th century. Pet rats are typically variants of
2480-608: The large number of living species, as of 2024, just four fossil species have been placed in Rattus proper: [REDACTED] [REDACTED] [REDACTED] [REDACTED] Rat species Rats are various medium-sized, long-tailed rodents . Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus Rattus . Other rat genera include Neotoma (pack rats), Bandicota (bandicoot rats) and Dipodomys (kangaroo rats). Rats are typically distinguished from mice by their size. Usually
2542-532: The midbelly. In addition, the medial thyroarytenoid muscle were focused at the midbelly while the lateral thyroarytenoid muscle MEPs were focused at the anterior third of the belly. The fourth and final feature that was cleared up was how the MEPs were distributed in the thyroarytenoid muscle. Laboratory rats have also proved valuable in psychological studies of learning and other mental processes (Barnett 2002), as well as to understand group behavior and overcrowding (with
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2604-579: The mouse is one of the most successful mammalian genera living on Earth today. In certain contexts, mice can be considered vermin . Vermin are a major source of crop damage, as they are known to cause structural damage and spread disease . Mice spread disease through their feces and are often carriers of parasites . In North America, breathing dust that has come in contact with mouse excrement has been linked to hantavirus , which may lead to hantavirus pulmonary syndrome (HPS). Primarily nocturnal animals, mice compensate for their poor eyesight with
2666-478: The potential source of "cryptic" SARS-CoV-2 lineages, due to unknown viral RNA fragments in sewage matching mutations previously shown to make SARS-CoV-2 more adept at rodent-based transmission. Rats are also associated with human dermatitis because they are frequently infested with blood feeding rodent mites such as the tropical rat mite ( Ornithonyssus bacoti ) and spiny rat mite ( Laelaps echidnina ), which will opportunistically bite and feed on humans, where
2728-427: The process. Initially, tons of arsenic trioxide were spread around thousands of farm yards to poison rats, but soon after the program commenced the rodenticide and medical drug warfarin was introduced, which is much safer for people and more effective at killing rats than arsenic. Forceful government control measures, strong public support and enthusiastic citizen participation continue to keep rat infestations to
2790-562: The publication of the rat genome sequence, and other advances, such as the creation of a rat SNP chip , and the production of knockout rats , the laboratory rat has become a useful genetic tool, although not as popular as mice . Entirely new breeds or "lines" of brown rats, such as the Wistar rat , have been bred for use in laboratories. Much of the genome of Rattus norvegicus has been sequenced. When it comes to conducting tests related to intelligence , learning, and drug abuse , rats are
2852-470: The rat population in Manhattan equals that of its human population was definitively refuted by Robert Sullivan in his book Rats but illustrates New Yorkers' awareness of the presence, and on occasion boldness and cleverness, of the rodents. New York has specific regulations for eradicating rats; multifamily residences and commercial businesses must use a specially trained and licensed rat catcher . Chicago
2914-401: The rat's larynx. The first being the location and attachments of the thyroarytenoid muscle, the alar cricoarytenoid muscle, and the superior cricoarytenoid muscle, the other of the newly named muscle that ran from the arytenoid to a midline tubercle on the cricoid. The newly named muscles were not seen in the human larynx. In addition, the location and configuration of the laryngeal alar cartilage
2976-435: The rat's tail demonstrate a higher proportion of living fibroblasts that produce the collagen for these fibers. As in humans, these tendons contain a high density of golgi tendon organs that help the animal assess stretching of muscle in situ and adjust accordingly by relaying the information to higher cortical areas associated with balance, proprioception, and movement. The characteristic tail of murids also displays
3038-548: The rats, of which the pilgrims also partake. Mouse A mouse ( pl. : mice ) is a small rodent . Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse ( Mus musculus ). Mice are also popular as pets . In some places, certain kinds of field mice are locally common. They are known to invade homes for food and shelter. Mice are typically distinguished from rats by their size. Generally, when
3100-623: The species brown rat , but black rats and giant pouched rats are also sometimes kept. Pet rats behave differently from their wild counterparts depending on how many generations they have been kept as pets. Pet rats do not pose any more of a risk of zoonotic diseases than pets such as cats or dogs . Tamed rats are generally friendly and can be taught to perform selected behaviors. Selective breeding has brought about different color and marking varieties in rats. Genetic mutations have also created different fur types, such as rex and hairless. Congenital malformation in selective breeding have created
3162-490: The species has been proposed, but does not include all species. The following phylogeny of selected Rattus species is from Pagès et al. (2010) . Berylmys bowersi Berylmys berdmorei Bandicota savilei Bandicota indica Rattus nitidus Rattus norvegicus Rattus exulans Rattus andamanensis Rattus argentiventer Rattus tiomanicus Rattus losea other Rattus spp. Rattus tanezumi Rattus rattus In contrast to
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#17328914201053224-419: The sponsors hope that once the rats are gone, it will regain its former status as home to the greatest concentration of seabirds in the world. The South Georgia Heritage Trust, which organized the mission describes it as "five times larger than any other rodent eradication attempted worldwide". That would be true if it were not for the rat control program in Alberta (see below). The Canadian province of Alberta
3286-425: The subject of investigation. Multiple studies have explored the thermoregulatory capacity of rodent tails by subjecting test organisms to varying levels of physical activity and quantifying heat conduction via the animals' tails. One study demonstrated a significant disparity in heat dissipation from a rat's tail relative to its abdomen. This observation was attributed to the higher proportion of vascularity in
3348-471: The tail's ability to function as a proprioceptive sensor and modulator has also been investigated. As aforementioned, the tail demonstrates a high degree of muscularization and subsequent innervation that ostensibly collaborate in orienting the organism. Specifically, this is accomplished by coordinated flexion and extension of tail muscles to produce slight shifts in the organism's center of mass , orientation, etc., which ultimately assists it with achieving
3410-449: The tail, along with ample muscle attachment sites along its plentiful caudal vertebrae , facilitate specific proprioceptive senses to help orient the rodent in a three-dimensional environment. Murids have evolved a unique defense mechanism termed degloving that allows for escape from predation through the loss of the outermost integumentary layer on the tail. However, this mechanism is associated with multiple pathologies that have been
3472-411: The tail, as well as its higher surface-area-to-volume ratio , which directly relates to heat's ability to dissipate via the skin. These findings were confirmed in a separate study analyzing the relationships of heat storage and mechanical efficiency in rodents that exercise in warm environments. In this study, the tail was a focal point in measuring heat accumulation and modulation. On the other hand,
3534-513: The wild. The term rat is also used in the names of other small mammals that are not true rats. Examples include the North American pack rats (aka wood rats ) and a number of species loosely called kangaroo rats . Rats such as the bandicoot rat ( Bandicota bengalensis ) are murine rodents related to true rats but are not members of the genus Rattus . Male rats are called bucks ; unmated females, does , pregnant or parent females, dams ; and infants, kittens or pups . A group of rats
3596-734: The wild. The genus Rattus is a member of the giant subfamily Murinae . Several other murine genera 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 64 extant species . A subgeneric breakdown of
3658-541: The work of John B. Calhoun on behavioral sink ). A 2007 study found rats to possess metacognition , a mental ability previously only documented in humans and some primates . 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. Since
3720-458: Was declared the "rattiest city" in the US by the pest control company Orkin in 2020, for the sixth consecutive time. It's followed by Los Angeles , New York, Washington, DC, and San Francisco . To help combat the problem, a Chicago animal shelter has placed more than 1000 feral cats (sterilized and vaccinated) outside of homes and businesses since 2012, where they hunt and catch rats while also providing
3782-466: Was described. The second feature was that the way the newly named muscles appear to be familiar to those in the human larynx. The third feature was that a clear understanding of how MEPs are distributed in each of the laryngeal muscles was helpful in understanding the effects of botulinum toxin injection. The MEPs in the posterior cricoarytenoid muscle, lateral cricoarytenoid muscle, cricothyroid muscle, and superior cricoarytenoid muscle were focused mostly at
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#17328914201053844-689: Was heritable in some way. Rat meat is a food that, while taboo in some cultures, is a dietary staple in others. Rats have been used as working animals. Tasks for working rats include the sniffing of gunpowder residue, demining , acting and animal-assisted therapy . Rats have a keen sense of smell and are easy to train. These characteristics have been employed, for example, by the Belgian non-governmental organization APOPO , which trains rats (specifically African giant pouched rats ) to detect landmines and diagnose tuberculosis through smell. Rats have long been considered deadly pests. Once considered
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