Sexual Maturity in the Female Bandicoot Isoodon-Macrourus (Gould) in Captivity

Abstract

In Queensland the bandicoot breeds throughout the year, but the breeding rate decreases from April to June. In this study, it was found that animals born from April to June gave birth to their first litter at an earlier age than those born in January-March, October-December or July-September: 204.0, 229.7, 244.0 and 286.8 days respectively. Similarly, the mean weights of the mothers of the four groups when giving birth to their first litter increased from 845.0 g to 873.0, 938.2 and 954.1 g respectively. The 11 bandicoots born in July-September formed two groups: five animals gave birth at 193.8 ± 7.3 days (range 176-212 days) at a weight of 734.0 ± 17.3 g (range 680-780 g) six animals gave birth at 364.3 ± 7.7 days (range 352-399 days) at a weight of 1137.5 ± 42.2 g (range 1020-1307 g). The latter group appeared to have delayed their sexual maturity during the decreased or non-breeding part of the year. Bandicoots which delay their sexual maturity are heavier when they produce their first litter than the faster developing animals. Therefore it is unlikely that decrease growth and development rates during April-June prevents the onset of sexual maturity. It is probable that the environmental cues which inhibit breeding in the adult female also affect the maturation of juvenile females.