I will admit something. I used to think Narwhals were fictional. I've asked a few people and they too, think Narwhals were fictional. I think it's because people refer to narwhals as "Unicorns of the sea", which is odd to me. Unicorns ARE fictional, so why would you compare a living thing to a mythical fictional thing? It's like saying "Camels are the leprechauns of the desert", or that "Polar Bears are the Dennis Haysbert of the arctic".
For fun facts about the mythical Dennis Haysbert, visit your local library!