Gestation length is between 38 and 42 days. Litters are normally 2 to 3 pups, but females may have up to 6 pups in a single litter. Other females within the social group may help in the birthing process and look after the pups. Pups are born with their eyes open and covered in fur. They will begin to leave the nesting area at about 3 days of age. Pups are weaned around 5 to 6 weeks and reach sexual maturity at about 6 to 9 weeks. A female can become pregnant at any time in the year and may have up to 12 litters in a year. Spiny mice can live for 4 to 5 years.