After gestation, premature bilby offspring climb into their mother’s pouch for 75 days before being cared for in a burrow for another 14 days until independence.
After their short, 14-day gestation, tiny, premature bilby offspring climb into their mother’s pouch and attach to a nipple where they remain for the majority of their time with their mother. During the 75 days the young bilbies remain in the pouch, the babies continue to grow at a very fast rate, reaching 200 grams by the time they leave the pouch.
Once the young emerge from their mothers pouch, they do not return. Many times, the female has already mated and a new neonate enters the pouch soon after the previous litter has left. These young juveniles are cached by the mother in one of her burrows where she returns regularly over the next two weeks to allow her babies to suckle and provide additional care.
After 14 days, the young leave the burrow and must fend for themselves with no additional parental care. It is estimated that only 25% of offspring produced will reach adulthood while the rest will become prey for predators or succumb to the elements.
Female bilbies reach sexual maturity at around five months old, or 560 grams, while males take around eight months, or at a weight of 800 grams, to reach maturity.
• Image | © Stephen Michael Barnett, Some Rights Reserved, (CC BY 2.0)
• Sources | (Brown, 2011; Environment Australia, 2004; Humble, 2006; Parks and Wildlife Commission of the Northern Territory, 1998; Pavey, 2006)