Perhaps its no surprise that the Narwhal inspires a lot of curiosity among scientists.

This arctic whale looks something like a unicorn of the sea, with a spindly tusk that can grow up to 9 feet long. This unusual appendage has been a focus of fascination and controversy for centuries.

Some researchers thought it was used to attract mates, hunt, breathe or maybe even hear, but no one knew for sure. Now a new study out of Harvard reveals the tusk actually acts like a sensory organ.

For more we're joined by Martin Nweeia, a marine mammal dental specialist and one of the authors of the study.