Muroidea in the context of "Mice"

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 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.

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 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).

The brown rat (Rattus norvegicus), also known as the common rat, street rat, sewer rat, wharf rat, Hanover rat, Norway rat and Norwegian rat, is a widespread, common species of rat. One of the largest muroids, it is a brown or grey rodent with a body length of up to 28 cm (11 in) long, and a tail slightly shorter than that. It weighs between 140 and 500 g (4.9 and 17.6 oz). Thought to have originated in northern China and neighbouring areas, it has now spread to all continents except Antarctica, and is the dominant rat in Europe and much of North America, having become naturalised across the world. With rare exceptions, the brown rat lives wherever humans live, particularly in urban areas. They are omnivorous, reproduce rapidly, and can be a vector for several human diseases.

Selective breeding of the brown rat has produced the fancy rat (rats kept as pets), as well as the laboratory rat (rats used as model organisms in biological research). Both fancy rats and laboratory rats are of the domesticated subspecies Rattus norvegicus domestica. Studies of wild rats in New York City have shown that populations living in different neighborhoods can evolve distinct genomic profiles over time, by slowly accruing different traits.

The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At over 870 species, it is either the largest or second-largest family of mammals, and has members throughout the Americas, Europe and Asia.

The genus Mus or typical mice refers to a specific genus of muroid rodents, all typically called mice (the adjective "muroid" comes from the word "Muroidea", which is a large superfamily of rodents, including mice, rats, voles, hamsters, gerbils, and many other relatives), though the term can be used for other rodents. They are the only members of the tribe Murini.

The Rat or Mouse (鼠) is the first of the repeating 12-year cycle of animals which appear in the Chinese zodiac, constituting part of the Chinese calendar system (with similar systems in use elsewhere). The Year of the Rat in standard Chinese is Chinese: 鼠年; pinyin: shǔnián. The rat is associated with the first branch of the Earthly Branch symbol 子 (zǐ), which starts a repeating cycle of twelve years. The Chinese word shǔ (鼠) refers to various small rodents (Muroidea), such as rats and mice. The term "zodiac" ultimately derives from an Ancient Greek term referring to a "circle of little animals". There are also a yearly month of the rat and a daily hour of the rat (Chinese double hour, midnight, 11:00 p.m. to 1:00 a.m.). Years of the rat are cyclically differentiated by correlation to the Heavenly Stems cycle, resulting in a repeating cycle of five years of the rat (over a sixty-year period), each rat year also being associated with one of the Chinese wu xing, also known as the "five elements", or "phases": the "Five Phases" being Fire (火 huǒ), Water (水 shuǐ), Wood (木 mù), Metal (金 jīn), and Earth (土 tǔ).