The female gives birth to an average litter of 5 to 6 young after a gestation period of 21 days. Births take place in "high nests", structures built about 100 to 130 cm above the ground. Construction on these nests begins during the spring and summer breeding season, and one nest is built for each litter of young. These nests are globular in shape, about 60 to 130 mm in diameter. They are formed of three layers of grass blades woven tightly together. The lining consists of finely shredded leaves and grass, which form a soft warm nest for the young. There is often more than one entrance, but these holes are kept closed by the female during the first week after parturition, and males are not allowed into the nest at all. Reproduction is usually concentrated during warmer, drier months, starting around April and ending in September. Females are polyestrous, undergo a postpartum estrus, and under the correct favorable conditions, can give birth several times in rapid succession. Because they have a short natural longevity, females usually live through only one or two reproductive seasons in a lifetime, but in captivity they have been known to experience up to nine. Gestation is about 17-18 days, as is the typical minimum interval between litters. The number of young per litter ranges from 1 to 13, but is usually around 3 to 8. The young weigh about a gram at birth, and are 2 cm long. The young are born naked, blind and altricial, but can hold onto a grass stalk as early as three days after birth. They open their eyes at 8 to 10 days, are weaned and leave the nest at 15-16 days, and reach sexual maturity in 35 days. Maximum known longevity in the wild is 16 to 18 months, with few individuals living past 6 months. In captivity, M. minutus can live to be just under 5 years old.
(Burton 1969; Grzimek 1990; Nowak 1993)
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual
Average birth mass: 0.9 g.
Average gestation period: 20 days.
Average number of offspring: 5.2.
Average age at sexual or reproductive maturity (male)
Sex: male: 37 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 40 days.