On the subject of nature shows, we were watching Planet Earth, Deep Ocean and Art asked, "Why do fish need to be in the water and why do they die if they're not in the water and why does the water need fish?" I explained that all things that are alive need something called oxygen and fish get their oxygen from the water. People get their oxygen from the air.
"Why can't fish be out of the water?" he asked again.
"Because they can only breathe the oxygen in the water. We breathe the oxygen in the air."
"How does a tiger breathe?"
"He breathes the air."
I don't know. I just loved that he randomly wanted to know about a tiger after all that fish talk.