Oestrous cycle and gestation length in the musky rat-kangaroo, Hypsiprymnodon moschatus (Potoroidae : Marsupialia)

Wild-caught male and female H. moschatus were maintained in a captive breed ing colony. Vaginal smears were taken three times a week until oestrous cyc les were detected and gestation lengths approximated. Thereafter, smears we re usually taken daily when oestrus was expected. The gestation period (con sidered to be the number of days from the detection of sperm in the smear u ntil the day young were found in the pouch) was found to last 19 days. Sper m were usually detected in the smear two days before the influx of semi-cor nified and cornified epithelial cells, which occurred 17 days before partur ition. A pre- or post-partum oestrus was not detected and females did not r eturn to oestrus until at least 6 days after the removal of the last pouch young. H. moschatus has the shortest recorded gestation for any macropod, and gest ation occupies approximately 75% of the oestrous cycle. The reproductive ph ysiology of H. moschatus is similar to that of most phalangerids, which may be indicative of a common ancestor.