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  • In Gansbaai, the largest white shark ever caught was at Danger Point and measured up to 5.9m. The exact world record white shark is a contested issue, but chances are it is between 6-7m.

  • If you see a white shark in the water don’t panic. Chances are high that the shark has already detected you and isn’t interested. White shark attacks are normally associated with poor visibility, so avoid murky conditions.

  • White sharks have a unique system called a “counter current heat exchange”, which keeps their body  tempreture +/- 7C above the surrounding water temperature. 

  • All sharks have an incredibly unique system on the tip of their nose called the “ampillae of Lorenzini”. These are small pores filled with a gel that transmits the electrical currents in the water to the shark’s brain so that it can assess its environment.

  • White sharks give birth to live young (not eggs), and they give birth to 6-8 pups at one time. Pups are usually between 1.0-1.5m in length and are born with teeth.

  • Body language has been a well documented form of shark communication and has identified body arching, jaw gaping, and other postures as specific social tactics.

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How many teeth does a white shark have?

Thursday, August 16, 2012 |  2 Comments

Author: Michelle Wcisel (Marine Biologist)
To Michelle, a born and bred American from Michigan, the sea resembles another planet within Earth where intelligent "extraterrestrial" beings and thriving systems flourish in the depths where there is neither oxygen nor sunlight. "So many of us gaze at the stars in wonder when we should be looking into our oceans!"

How many teeth does a white shark have in its lifetime?  Seems like an easy question, but when you consider that we don’t even know where white shark give birth (which is far more important!), you begin to realise that there are no easy answers when sharks are concerned.  Let me take you through the physiology and the math, and show you how difficult this easy looking question actually is.

In order to tell you how many teeth a white shark has over its lifetime, we’ll need to do some sort of calculation like this one I’ve just made up (it is a blog afterall):

Rate of tooth loss X average life span of the shark = how many teeth over a lifetime. 

That's easy enough, but do you see the problem yet?  If not, read on...

We definitely know that white sharks have about 24 exposed teeth on their top and lower jaws, respectively.  That’s these:



But behind these 48ish teeth, there can be 5ish rows of developing teeth behind them, like this:



Sharks continually lose their teeth over time and the developing teeth will then rotate in and replace them.  This rate of tooth loss most probably has to do with what the sharks are chomping on, so its pretty difficult to define exactly.  But for the sake of blogging, how would one go about conducting a study to answer this rate of tooth loss conundrum?  I could grow my own white shark jaws in a lab, apply the known white shark bite forces to various prey items to see how many teeth fall out each time, then apply that to the general diets of various shark populations world wide!  But alas, not terribly feasible however awesome that may be.  So an actual rate of tooth loss is a bugger.  But since this is a blog, I’ll just make up an answer of 19 teeth a week.  Why 19?  Because its the jersey number of the greatest hockey player of all time.  Plus, we also know a shark can eat at least 6 seals in a sitting, and they probably lose a few teeth per seal (check out the image at the bottom!)

OK, but what about our other factor – average lifespan of a white shark.  I am afraid we don’t have a real grasp on this number either!  My next shark fact blog will go into this in greater detail, but it's generally accepted that white sharks live longer than 30 years... which isn’t terribly helpful for our question.  Considering that an orange roughy was aged at 149 years and this lungfish is at least 80 years old, we actually know very little about fish life histories!  But again, for the sake of blogging, lets say we have a 30 year old shark. 

So 19 teeth a week = 988 teeth a year x 30 years = 29,640 teeth per year.  Let's add (48 teeth x 5 rows of development) = 240 currrent teeth.  240 + 29640 = 29880 teeth during a white shark's lifetime!

Now that's a sciencey looking number, but it's just a number with very little (if any) scientific basis.  Remember this story the next time you see an outragious number in any shark fact.  When we know so little about them, even the easy looking questions are difficult. 



This white shark sent a tooth flying at it went slamming into the decoy. 

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