Are Narwhal tusks the reason for the unicorn legend?

At one time, it is surmised that a Viking traded a horn with a European trader who assumed that it came from a unicorn, and thus the myth was born. As this whale lived only in the far north, the Vikings were able to exploit the legend of the unicorn and the belief that the narwhal's horn held magical properties. read more

I doubt it - unicorns were part of human legend long before narwhals were discovered to exist. The parallel to unicorns was made when they were found out, and I dare say that long horn is the only point they have in common. Narwals don’t look like unicorns at all. read more

In fact, the narwhal is also known as the “unicorn of the sea,” and its tusk, which is an elongated tooth that projects forward from the mouth and is carved along its length by a left-handed spiraling groove, inspired belief in the mythological one-horned unicorn. read more

In medieval Europe, some people believed that narwhal tusks were the horns from the legendary unicorn. Whilst in the north, the tusk simply had a practical or decorative use, on the European continent, the tusk was believed to have superb magic powers, like healing from poison or curing certain diseases. read more