Burramys parvus follows a low fecundity, high longevity life strategy. The mountain pygmy possum has a non-breeding season from January-April, when it gain sweight for the coming winter and the young disperse. The inactive season, from May-September, is hibernation season for B. parvus. From September through December, B. parvus is in an active season of breeding. B. parvus females are polyestrous but limited to one litter per year by the need to store fat reserves for hibernation. Without sufficient fat, the females die. In response to fat reserve limitations, B. parvus synchronizes its reproduction with spring, when nutrient rich Bogong moths are abundant. Breeding occurs annually for many consecutive years. Reproducing females have been found up to 12 years of age, which makes them one of the longest lived small terrestrial mammals.
Studies have successfully mapped out the reproductive timeline of the mountain pygmy possum (Mansergh and Scotts 1990). Mating occurs between late September and mid October. Female estrous lasts ~20 days. After fertilization, a gestation period of 13-16 days ensues, followed by birth in the last week of October of four altricial young (Mansergh and Scotts 1990). The young have well developed forelimbs and heads for traveling from the cloaca to the pouch. The female cleans a trail for the young to the pouch, where the young attach to a teat (Broome and Mansergh 1994). Frequently the female bear smore than four young, leading to more offspring than teats. Under these circumstances, the 'slowest' young will not have a teat when it arrives in the pouch, and will die. The lactation period lasts 30 days, with a subsequent nesting period of 30-35 days (Strahan 1995). The young are fully weaned and independent after 65 days. Young disperse between January and March (Lee and Cockburn 1985). At approximately 1 year of age, the young begin mating. Only 50% of the reproducing young will survive, due to the inability of younger B. parvus to maintain fat reserves for hibernation (Mansergh et al. 1990). By their second summer, young are fully capable of sustaining themselves for both activities (Strahan 1995).
Average gestation period: 15 days.
Average number of offspring: 3.5.
Average age at sexual or reproductive maturity (male)
Sex: male: 320 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 320 days.