New research discovers the twisty secret behind the narwhal's unusually straight tusk | CBC News
The narwhal tusk is a true oddity in the natural world. Reaching up to three metres in length, the tusk is an upper tooth that grows through the whale's lip on the left side. And it is the only mammal tusk that grows perfectly straight, with no curves. A team of international researchers believe they have figured out why it grows so straight — and the answer lies in its unique pattern of opposing spirals. “This was really the first time that we could prove that this was the case and that there w...