Naturespeak A naturalist's view of the world

June 28, 2007

Conradulations

Filed under: Uncategorized — wykes @ 10:09 pm

My spell check went into conniptions when I typed in the title “Conradulations” for this piece. I chose to ignore the wiggly red error line in this case because I meant what I wrote. It is not my intention to send Congratulations (although I do wish that to all those high school grads out there), but instead to call attention to a snail’s tongue known as a radula.  This being the case, any discussion about a radula could be considered as a “radulation” and acknowledgement of a radula job well done would be a Conradulation.

  It so happens that I was watching a Mystery snail crawl up my aquarium glass and marveling at it’s constantly moving tongue. Take a look at my drawing and you’ll see what I saw (look here). The most notable feature is the expansive foot pad, but it is the long snout, protruding out from between the tentacles, that gives the animal its personality.  At the end of this snout, or proboscis, is the mouth opening is pressed up against the glass like the end of a vacuum hose. Inside the mouth is a tiny pink tongue called a radula. This tongue is in constant back and forth motion and is the key to snail feeding behavior.

  Most snails, like this giant Mystery variety, live by grazing on microscopic plant life such as diatoms and algae.  Grazers need teeth, and there are hundreds (sometimes thousands) of them arranged row upon row on the tongue.  The snail tongue term of Radula is based on the latin word for scraper, which is an apt description of this file-like appendage. Take a look here at this detailed view showing the rows of sharp microscopic hooks.  Snails got teeth – lot’s of ‘em.

  In technical terms, the toothed structure is called as “chitinous ribbon,” but let’s just keep on calling it a tongue. By moving the whole tongue forward and back, the critter rasps off the algae strands and then pushes them forward where they are sucked down into the throat. Our mystery snail moves his snout from side to side in order to graze a pathway across the glass. Each species has a very specific arrangement and number of teeth, but only people with too much time on their hands spend that time counting snail teeth.

   As would be expected, this dental tool set is constantly wearing down.  New teeth are produced from the back of the tongue as quickly as those in the front wear out.  Tongue tooth production is constant and rapid. Basically we have a tooth conveyer belt going on here.  

  I sense at this point that you may be reaching the tolerance limit for snail tooth talk, so I will leave the subject for you to mull over (or bring up at the breakfast table). Just in case you’ve got some unsatisfied curiosity about Mystery Snails, here’s a great site to view. There are over 36 different species found across the world (another thing to bring up during lunchtime discussion). The individual that I was lip-reading appears to be the Oriental Mystery Snail – an introduced species from S.E. Asia, but there are some 17 native types in North America. To complete your meal discussion list, perhaps you can also bring up the fact over dinner that Mystery Snail males have a right eye stalk that is modified as a…well, let’s just say… as a “reproductive organ.” Now there’s some food for thought.

 Whether or not you want to think about such nasty reproductive details, Mystery snails are members of a family that actually bear their young live. In other words, they do not lay eggs, but pop out complete little snailets ready to enter the big wide world as fully equipped tongue eaters. To those new graduates I say “Conradulations.”

1 Comment »

  1. I wish I could think of something clever to write, but yeah, you pretty much said it all.

    Comment by Dentists West Hollywood — March 4, 2010 @ 5:39 pm

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