Sing unto the LORD a new song, and his praise from the end of the earth, ye that go down to the sea, and all that is therein; the isles, and the inhabitants thereof.(Isaiah 42:10) KJV
Australia was part of Pangaea for 101 years after Noah’s flood. That’s how Monotremes got there. If you’ve been vexing Creationists with the issue of Australia’s unique fauna: time’s up, find a new game. Sing a new song.
Monotremes, a group of mammals which includes the Duck-billed Platypus, are indigenous to Australia and New Guinea. They’re unique among the Mammals because they lay eggs rather than give birth to live young. They’re considered to be an evolutionary link between the reptiles and mammals, supposedly evidence of the reptile-mammal transition.
If you ever get into discussion of creation vs. evolution on Twitter you’ll find that the atheist science trolls (ASTs) are all trained in the same propaganda and sooner or later one of them will presume to demonstrate their intellectual superiority by asking a stupid question like: how did Kangaroos swim to Australia?
Tragically the present trend in creationism is to conflate Noah’s flood with Peleg’s tectonics and so they can’t answer the question effectively.