The Narwhals are whales, and so are classified within the Order Cetartiodactyla (even-toed) of mammals. The interesting thing they have is a tusk ( really a long canine) coming out from their mouth that looks exactly like the fabled Unicorn’s horn. Research videos have come out that they use this tusk to slap fish unconscious while hunting them.
Both this whale and the Arabian Orynx, notice the picture below where it looks like the horn is growing out of its forehead….
….gave birth to the legend of the unicorn.
Medieval Europe was rife with Narwhal tusks being sold as unicorn horns. This led to really intensive whaling for there poor creatures and now they are threatened in their ranges over the northern Atlantic and Arctic Ocean.