Fast Fiction

Marine Biology Mystery Solved: Function of “Unicorn” Whale’s 8-foot Tooth Discovered

After hundreds of years of guessing, Harvard Medical School announced what they believe to be the purpose of the Narwhal’s tusk.

The Narwhal is a small toothed whale (member of the Odoncete suborder) that lives in the Arctic and North Atlantic. Males grow to be about 15 feet and weigh about 3,500 pounds and females slightly smaller at 13 feet and a slimmer 2,000 pounds. They are unique in the world of cetaceans in that they have a single tusk, which is a modified tooth grows in corkscrew fashion from their left jaw. Many are up to nine feet long, which means that they may be two thirds as long as their body. Unlike most Acrtic whales, the Narwhal does not migrate south but they do move around in larger groups within the Arctic Ocean from the shores to more open ocean as ice floes cover areas.

Nweeia 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. There is no comparison in nature and certainly none more unique in tooth form, expression, and functional adaptation.

This is a totally cool adaptation as far as I’m concerned. Much like a lizard or snake uses their tongue to taste the air, this discovery about the sensory sensitivity of the Narwhal’s tooth must makes their adaption to their habitat all the more admirable.

UPDATE: Amazingly detailed article from the NY Times now up!