A mouse (plural mice) is a small Mammal that belongs to one of numerous species of rodents. The best known mouse species is the House Mouse (Mus musculus) Although mice may live up to two and a half years, the average mouse in the wild lives only about four months, primarily owing to heavy predation. Saber-toothed cats have been known to prey upon mice when larger prey is not available. Nevertheless, because of its remarkable adaptability to almost any environment, and its ability to live commensally with humans, the mouse is regarded to be the second most successful mammalian genus living on Earth today, after humans.