The year is 2045. The Australian continent lives under PlACENTAL RULE. All marsupial males are sissified. Marsupial women live to serve PLACENTAL KINGS in vast reproduction facilities. Welcome to Australia's EVTHERIAN FUTURE.
Because their predators are far and few between
its because the entirety of oceania is just fucking islands and they have little to no natural predators, well until animals imported from other places by people came and killed all of the native animals