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rat

rat, name applied to various stout-bodied rodents, usually having a pointed muzzle, long slender tail, and dexterous forepaws. It refers particularly to the two species of house rat, Rattus norvegicus, the brown, or Norway, rat and R. rattus, the black, roof, or Alexandrine, rat. Both species originated in Asia, but have spread throughout the world, mostly on board ships. The black rat was common in Europe in the Middle Ages and has been historically implicated in the spreading of plague, but recent research has suggested that the great gerbil or another rodent of Central Asia may have been the source. The black rat has since been largely displaced in cooler regions by the brown rat, which reached Europe early in the 18th cent. and North America by 1775.

The brown rat is the larger of the two, growing up to 10 in. (25 cm) long excluding the naked, scaley tail and sometimes weighing more than a pound (.5 kg). It is commonly brown with whitish underparts and pink ears, feet, and tail. It is a poor climber, but an excellent burrower and swimmer; it is found in the damp basements and sewers of most temperate zone cities. The laboratory white rat is an albino strain of the brown rat.

The black rat is commonly dark gray. It reaches a maximum length of 8 in. (20 cm) and has a longer tail and larger ears than the brown rat. A good climber, the black rat inhabits attics and upper floors in warm areas; it is the common rat of the Mediterranean region, the SE United States, and Central and South America.

Rats are omnivorous, aggressive, intelligent, adaptable, and extremely fecund. Females produce as many as 8 litters each year with as many as 20 young per litter. The gestation period is three weeks, and the young reach sexual maturity in about two months. Rats may live as long as four years. They are social animals but sometimes fight among themselves.

Rats live mostly in and around human settlements, where they have few natural enemies and an abundant source of food. They invade food supplies and cause widespread destruction; they also spread human diseases such as typhus and tularemia. Despite human efforts to exterminate rats, the house rat population is probably equal to the human population.

Besides the house rats, the genus Rattus contains several hundred wild-living species. In addition, many other members of several different rodent families are called rats, e.g., the bandicoot rat, the wood rat, or pack rat, the rice rat, the muskrat, and the kangaroo rat. House rats are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Rodentia, family Muridae.

See also mouse.

See H. Zinsser, Rats, Lice and History (1935); S. A. Barnett, The Rat, a Study in Behavior (1963).

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rat

rat / rat/ • n. 1. a rodent (Rattus and other genera, family Muridae) that resembles a large mouse, typically having a pointed snout and a long, sparsely haired tail. Some kinds have become cosmopolitan and are sometimes responsible for transmitting diseases. 2. inf. a person regarded as despicable, esp. a man who has been deceitful or disloyal. ∎  an informer. 3. a person who is associated with or frequents a specified place: mall rats. 4. a pad used to give shape or fullness to a woman’s hair. • interj. (rats) inf. used to express mild annoyance or irritation. • v. (ratted , ratting ) [intr.] 1. [usu. as n.] (ratting) (of a person, dog, or cat) hunt or kill rats. 2. inf. desert one's party, side, or cause. 3. give (hair) shape or fullness with a rat.

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"rat." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. 21 Aug. 2017 <http://www.encyclopedia.com>.

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rat

rat the rat has traditionally been taken as the type of a cunning and vicious animal, especially (as in the saying that rats desert a sinking ship) one ready to betray a cause, or to rat.
rat pack a group of journalists and photographers who pursue celebrities in a relentless or aggressive way.
The Rat Pack was the name given to the group of 1960s actors that included Dean Martin, Frank Sinatra, and Sammy Davis Jr.
rat race a way of life in which people are caught up in a fiercely competitive struggle for wealth or power.
rat run a minor, typically residential street used by drivers during peak periods to avoid congestion on main roads.

See also rats.

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"rat." The Oxford Dictionary of Phrase and Fable. . Encyclopedia.com. 21 Aug. 2017 <http://www.encyclopedia.com>.

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rat

rat Any of numerous small rodents found worldwide. Most species are herbivorous. The best known are the black rat (Rattus rattus) and brown rat (R. norvegicus), both of the family Muridae. They carry diseases and destroy or contaminate property and food. Both live everywhere that humans live.

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"rat." World Encyclopedia. . Encyclopedia.com. 21 Aug. 2017 <http://www.encyclopedia.com>.

"rat." World Encyclopedia. . Encyclopedia.com. (August 21, 2017). http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/rat

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rat

rat1 rodent of the genus Rattus. OE. ræt, reinforced in late ME. from (O)F. rat :- Rom. *rattus; ult. orig. unkn. In ME. raton (mod. dial. ratton, ratten) was the more frequent word. (- OF. raton, f. rat with augm. suffix).

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"rat." The Concise Oxford Dictionary of English Etymology. . Encyclopedia.com. 21 Aug. 2017 <http://www.encyclopedia.com>.

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rats

rats rats desert a sinking ship people hurry to get away from a failing enterprise or organization; the idea is that as a ship sank rats would be seen emerging from it to try to seek safety.

See also rat.

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"rats." The Oxford Dictionary of Phrase and Fable. . Encyclopedia.com. 21 Aug. 2017 <http://www.encyclopedia.com>.

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rat

rat2 (mild imprecation) XVII. repr. affected pronunc. of ROT vb.

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"rat." The Concise Oxford Dictionary of English Etymology. . Encyclopedia.com. 21 Aug. 2017 <http://www.encyclopedia.com>.

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rat

rat
1. (Old World) See MURIDAE.

2. (New World) See CRICETIDAE.

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"rat." A Dictionary of Zoology. . Encyclopedia.com. 21 Aug. 2017 <http://www.encyclopedia.com>.

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rat

ratat, bat, brat, cat, chat, cravat, drat, expat, fat, flat, frat, gat, gnat, hat, hereat, high-hat, howzat, lat, mat, matt, matte, Montserrat, Nat, outsat, pat, pit-a-pat, plait, plat, prat, Rabat, rat, rat-tat, Sadat, sat, scat, Sebat, shabbat, shat, skat, slat, spat, splat, sprat, stat, Surat, tat, that, thereat, tit-for-tat, vat, whereat •fiat • floreat • exeat • caveat •Croat, Serbo-Croat •Nanga Parbat • brickbat • dingbat •combat, wombat •fruitbat • numbat • acrobat • backchat •whinchat • chitchat • samizdat •concordat • Arafat • Jehoshaphat •butterfat • Kattegat • hard hat •sun hat • fat cat • hellcat • requiescat •scaredy-cat • Magnificat • copycat •pussycat • wildcat • bobcat • tomcat •Sno-Cat • polecat • muscat • meerkat •mudflat • cervelat •doormat, format •diplomat • laundromat • Zermatt •Donat • cowpat

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"rat." Oxford Dictionary of Rhymes. . Encyclopedia.com. 21 Aug. 2017 <http://www.encyclopedia.com>.

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