A house mouse that is a pet has an average life span of about two years. There have been mutant and calorie-restricted mice in captivity that have lived for up to five years.
Wild house mice (Mus musculus) that have been captured live up to four years while already in captivity. On their own, most wild mice live for only 12 to 18 months. Predators and other factors are the reasons for this shorter life span among wild mice. With pet mice, a healthy diet can significantly increase their life span. Obesity in mice can overload their heart and cause an early death.