Rats Wallpaper, #12422

Rats are various medium sized, long-tailed rodents of the superfamily Muroidea. "True Rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus. Many members of other rodent genera and families are also called Rats and share many characteristics with true Rats.Rats are distinguished from mice by their size; Rats generally have bodies longer than 12 cm (5 in).The best-known rat species are the Black Rat (Rattus rattus) and the Brown Rat (Rattus 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 lb) in the wild.The term "rat" is also used in the names of other small mammals which are not true Rats. Examples include the North American pack Rats, a number of species loosely called kangaroo Rats, and others. Rats such as the Bandicoot rat (Bandicota bengalensis) are murine rodents related to true Rats, but are not members of the genus Rattus. The widely distributed and problematic commensal species of Rats are a minority in this diverse genus. Many species of Rats are island endemics and some have become endangered due to habitat loss or competition with the Brown, Black or Polynesian rat.