Rats and mice, especially the guayabita (Musmusculus), an extremely destructive rodent, are very abundant.
MOUSE, in its original sense probably the name of the semidomesticated house-mouse (Musmusculus), the type of the genus Mus and of the family Muridae.
Zoologically, there is no distinction between mice and rats; these names being employed respectively for most or all of the smaller and larger "mouselike" and "rat-like" representatives of the Muridae, whether they belong to the genus Mus or not.
Those included in the genus Mus, are dealt with in the article RODENTIA.
With the exception of Madagascar, the genus Mus ranges over practically the whole of the Old World, having indigenous representatives even in Australasia; while the house-mouse, with man's involuntary aid, has succeeded in establishing itself throughout the civilized world.