Why?
Prove they didn't.
Wait.
How did I end up on the evo or religion forum anyway?
Never mind.
No, you have the outrageous claim that goes against logic, you prove that there was an ark. Where is it? How did the animals get home? What did they eat? Where are the fossils? How could you build a boat out of wood that would be structurally sound enough and large enough to hold all the animals.
You have to answer the questions to prove the fable, I just have logic and science on my side.