Noahs flood, how did animals get to australia after this world wide flood?

Like many tales in the bible the Noah story is a myth borrowed and adapted over time to teach spiritual lessons. There are many flood myths and many claim it was world wide. Floods are common occurrences and are their devastation and destruction is easily understood. When you have no idea the extent of the world and all you know is flooded, it becomes a world wide flood to you. It also adds an important element to the myth's lesson or 'truth' being taught.