Reproductive behaviour
Greater bilbies are polygynous with the dominate male mating with equal females whilst the least dominant male mates with the loswer female. Coitus is initiated by the male continually sniffing the female around the flanks, face, shouders and under the tail while also licking the urogenital opening (Moritz et al. 2003). In return females may sniff the male, remaining still or activley reject the male. Sexual intercourse primarly takes place undergroung although has been observed above ground (Johnson 1989).
Breeding season
Although bilbies are capable of breeding year round, females tend to come into season only during good conditions (Moritz et al. 2003). During favourable conditions a female may produce up to 4 litters yearly, each generally made up of 1-2 offspring (Johnson 1989).
Sexual maturity and Gestation
Female sexual maturity takes place at around 4-7 months whereas males reach sexual maturity at around 5 months to 1 year. The female greater bilby oestrus cycle generaly lasts for 21days and Gestation last for only 14 days (Johnson 1989).
Embryology and Development
In true marsupial form, offspring are born with precocial forelimbs and altricial hindlimbs of which the forelimbs assiting the young with the passage from the urogenital opening to the pouch. Once arriving at the pouch the young attaches itself to a teat not being used and remain attached for around 75-80 days. At around day 69, the formley naked young become furred and eyes open completley and leave the pouch at around 200g (Johnson 1989).
Pouch life
Whilst in the pouch nourishment is acquired from the mothers milk with nipples both inside and hanging out of the pouch. Each nipple produces milk of different compositions adapted to raise young at different stages (Southgate et al. 2000).
Life in the real world
Termination of pouch life occurs at around 80 days or 200g and generally lasts for a period no longer than 5 days. For around 2 weeks after eviction young are still suckled regularly from outside the pouch inside one of the females nursery burrows (Johnson 1989). Following this period juveniel Greater bilbies emerge from the burrow independant and leave (Moritz et al. 2003).