If the young in the pouch should die within five months, the embryo resumes development and is born in 24 to 27 days. If the first young lives, the embryo degenerates when the female enters anestrus. Under good conditions the second embryo can resume growth after the first young is successfully raised. The young leaves the pouch between 175 to 195 days old, but will return if alarmed or cold. Behavior On Rottnest Island the populations are organized into family groups.
Adult males dominate the family and also form a linear hierarchy among themselves.
Although the hierarchy is usually stable, on hot summer days the adult males fight intensively for the best shelters. Availability of such sites is the main factor in limiting the populations. There is little evidence of territoriality, and groups of 25 to 150 individuals may have overlapping home ranges, especially during the summer when many groups concentrate around available fresh water. At night, when quokkas emerge to feed, they makes runways and tunnels through dense grass and undergrowth. They hop on their hind legs when moving quickly and do not use their tail as a third prop when moving slowly, unlike kangaroos and large wallabies.