Notable Narwhals

The beluga whale (see previous post) is one of two members of the Monodontidae family and is a 'toothed' whale.  The other member of the family is the narwhal, an unusual cetacean with a spiral tusk that looks like the 'sword' of a swordfish.  The tusk is actually an enlarged tooth that grows out through its upper lip.  (OUCH)  The male narwhal's tusk can grow to over 8 feet long.  The females may have a much smaller tusk, but most females don't have one at all.  The male can also develop a second tusk, but this is more unusual.

Photo by K. Bruce Lane  Source: Wildlife North America

That narwhals have a tusk is known, exactly what it does with it?  Not so much.  It has been theorized that it is used for breaking up pack ice.  However, that doesn't really fly since narwhals can become entrapped in ice.  It has also been thought that it is used as part of the mating ritual and the males use it to fight rivals over females.  But observers that witness 'tusking' claim narwhals don't really seem to be fighting.  Some people think it looks more like they are rubbing their tusks together to clean them.  It was believed that perhaps the tusk is for decoration only, and that the longer, thicker the tusk the better to attract a female looking for a mate or determine hierarchy.  However, in 2005 Martin Nweeia "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 in tooth form, expression, and functional adaptation."  (from an article by Leah Gourley in the Harvard Gazette. )

Replica of a narwhal tusk  Source:  Educational Biofacts

Like belugas, the narwhal inhabits Arctic waters, although their territory is slightly smaller concentrated in Atlantic and Russian northern waters.  Also like the beluga it is a bottom feeder and its diet consists of cod, squid, flatfish, and shrimp.  It has also been known to go after baby seals if food is scarce.  Narwhals are also capable of diving deeper than belugas.  In fact, narwhals have made some of the deepest dives ever recorded for a marine mammal - many dives over 4,000 feet.

Source:  Narwhal News Network

One of the most unusual stories about the narwhal is that because of its tusk, the legend of the unicorn began.  Not exactly how I picture a unicorn, but the narwhal certainly has an air of mystery to it.