A fancy mouse (Mus musculus domestica) is a domesticated form of the house mouse (Mus musculus), one of many mice species, usually kept as a type of pocket pet. Fancy mice have also been specially bred for exhibiting, with shows being held internationally. A pet mouse is inexpensive compared to larger pets, and even many other pet rodents, but mice are comparatively short-lived: typically only 2 to 3 years.