House mice have a polygynous mating system. The recent discovery of ultrasonic songs produced by male mice, when exposed to female sex pheromones, suggests that this behavior may be involved in mate choice.
Mating System: polygynous
Mus musculus is characterized by tremendous reproductive potential. Breeding occurs throughout the year, although wild mice may have a reproductive season extending only from April to September. The estrous cycle is 4-6 days long, with estrus lasting less than a day. Females experience a postpartum estrus 12-18 hours after giving birth. Females generally have 5-10 litters per year if conditions are suitable, but as many as 14 have been reported. Gestation is 19-21 days but may be extended by several days if the female is lactating. Litters consist of 3-12 (generally 5 or 6) offspring, which are born naked and blind. They are fully furred after 10 days, open their eyes at 14 days, are weaned at 3 weeks, and reach sexual maturity at 5-7 weeks. Average life span is about 2 years in captivity, but individuals have lived for as long as 6 years. In the wild, most mice do not live beyond 12-18 months.
Breeding season: Throughout the year
Range number of offspring: 3.0 to 12.0.
Average number of offspring: 5.0.
Range gestation period: 21.0 (high) days.
Average weaning age: 21.0 days.
Range age at sexual or reproductive maturity (female): 5.0 to 7.0 weeks.
Range age at sexual or reproductive maturity (male): 5.0 to 7.0 weeks.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); viviparous
Average birth mass: 1.25 g.
Average number of offspring: 7.
Young mice are cared for in their mother's nest until they reach 21 days old. Soon after this most young mice leave their mother's territory, though young females are more likely to stay nearby.
Parental Investment: altricial ; pre-fertilization (Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)