The Control of Pouch Vacation in the Tasmanian Bettong, Bettongia-Gaimardi

Abstract

In continuously breeding marsupials it is possible for successive young to occupy the pouch simultaneously. Although this rarely occurs in nature, it is most likely in some macropodids. Experiments by others have suggested that it is the pouch young which determines the duration of lactation and pouch occupancy. The female Bettongia gaimardi exhibits a precise sequence of events on the night her young vacates the pouch. Initially, the pouch muscle tightens, preventing re-entry by the large young, this is then followed by birth and/or oestrus. When pouch vacation is not followed by birth and/or oestrus, young have stayed in the pouch significantly longer. Experiments in which furred pouch young are replaced by others of different ages have shown that the replacements remain in the pouch until the night of birth and/or oestrus, regardless of their age. This indicates that in this species physiological events in the mother are at least partly responsible for determining the duration of pouch life.