At one time, Vikings made a lot of money by selling narwhal horns to European royalty as unicorn horns. Of course, they were secretive about where they obtained the horns. We know more about narwhals now, a lot more. They are a type of whale in which one tooth grows into a long, straight tusk -but only in the males. But what purpose does it serve? A new experiment points to the theory that the tusk is a sense organ.
Part of their argument is based on the anatomy of the tusk. Rather than being a solid hunk of bone, it’s shot through with nerves. And it appears specially adapted to bring those nerves nearly in contact with sea water. In us and in other mammals, teeth are armored in sheets of enamel. Narwals don’t have enamel on their tusks. Instead, the surface of the tusk is covered in fine channels that can bring water down into the tusk’s interior, close to the nerve endings there. And some of those nerve endings have the structure you find in nerves sensitive to pain.
An experiment in which scientists manipulated the water around narwhal’s tusks appears to prove the theory. Read about it and a whole lot more we now know about narwhals at The Loom.