Gilbert's potoroo
The female potoroos can have two babies in a year, but only carry one at a time. They can keep a second embryo in a state of diapause while the first embryo is growing. If the first baby does not survive, the second baby can start growing right away. It is not known how long gestation is for Gilbert’s potoroo, but it is thought to be the same as the long-nosed potoroo; about 38 days. The baby potoroo is only about  long when it is born. It lives in its mother's pouch for about 4 months.