* Astronomy

Martin Nweeia, DMD, DDS, has answered a marine science question that has eluded the scientific community for hundreds of years: why does the narwhal, or "unicorn," whale have an 8-foot-long tooth emerging from its head, and what is its function?

He has discovered that the narwhal's tooth has hydrodynamic sensor capabilities. Ten million tiny nerve connections tunnel their way from the central nerve of the narwhal tusk to its outer surface. Though seemingly rigid and hard, the tusk is like a membrane with an extremely sensitive surface, capable of detecting changes in water temperature, pressure, and particle gradients. Because these whales can detect particle gradients in water, they are capable of discerning the salinity of the water, which could help them survive in their Arctic ice environment. It also allows the whales to detect water particles characteristic of the fish that constitute their diet.

In the past, many theories have been presented to explain the tooth's purpose and function, none of which have been accepted as definitive. One of the most common is that the tooth is used to display aggression between males, who joust with each other for social hierarchy. Another is that the tooth is a secondary sexual characteristic, like a peacock's feathers or a lion's mane.

Nweeia's findings point to a new direction of scientific investigation.

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