December 13, 2005 | David F. Coppedge

Marine Unicorn Tusk is a Precision Sensor

Unicorns exist – in the north sea.  Not horses, these are marine mammals, called narwhals, a kind of whale that sports a unique spiraling tooth that gives them the appearance of a unicorn.  Scientists have puzzled for centuries over what these tusks are for.  Leading theories were that males used them for joisting to defend territory, or they were artifacts of sexual selection.  Now, scientists from Harvard School of Dental Medicine under Martin Nweeia think they have solved the mystery.  The tusk is lined with ten million tiny nerve connections that give this unusual tooth an extremely sensitive probe into the temperature, salinity and pressure of the icy water in which they live.  With the proteinaceous membrane on the outer surface connected to the nerves inside, it acts as an antenna of sorts, guiding the animals to their prey in the deep water or sensing the environment at the surface.
    The tooth on males can be up to nine feet long, yet is resistant to breakage.  It grows in a spiral pattern straight out without curving, as with elephant tusks.  No other mammal has a tooth anything like it; the press release states, “there is no comparison in nature and certainly none more unique in tooth form, expression, and functional adaptation.”  Tooth scientists are interested in learning how the narwhal tooth remains both strong and flexible (it can bend a foot without breaking), for possible applications in restorative dental materials.  See also the reports on LiveScience, National Geographic News, and Science Daily.  Narwhals have also been seeing rubbing one another’s tusks for perhaps some pleasurable or social purpose humans cannot imagine.

No missing links.  Functionally useful.  Optimally designed.  The truth about the tooth required discounting evolutionary stories and going into the Arctic to study these animals and their structures up close, to determine their design.  Chalk up another study that assumed there was a purpose beyond the just-so stories, and did good scientific work to uncover it.  Now we can all be amazed a little more.

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Categories: Mammals

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