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Hadrosaur tails

Let me preface this by saying that I'm no expert on hadrosaurs, and 
what follows is only partially informed speculation.

That said, I find it hard to believe that the tails of hadrosaurs 
were their primary defense.  The main problems I see with a defensive 
use are the tail's stiffness and thinness.  Other dinosaur groups 
that (we assume) used their tails for defense, like stegos, ankylos, 
and probably diplodocid sauropods, tend to have very mobile tails.  
Ankylo tails are stiff out at the end, near the club, but the first 
half of the tail looks like it could probably bend very well.  A 
hadrosaur would have to rotate *the entire body* to smack something 
with its tail.  Surely this would have been less accurate than a 
mobile tail.  And even if the hadro managed to connect, I doubt that 
a tail that seriously thin would do much damage.  I'm not too 
knowledgable in such matters, but I would be very surprised if the 
average hadrosaur tail packed more than a few hundred pounds.  
Admittedly that's a lot of weight, but it's all spread out in a very 
thin layer.  I've looked at both hadrosaur tails and tyrannosaur legs 
up close, and I just can't believe that a sail-tail a few inches thick 
would make much impression on a tyrannosaur's tree-trunk-like legs.  
The hadrosaur's ossified tendons might keep the tail from snapping, 
but this seems to me to be a case of the meager force hitting the 
immovable object.

Now, I'm sure that if a hadrosaur was about to get eaten and had no 
other choice it might have employed its tail as a weapon, but 
the hadrosaur tail seems poorly designed for such use.  I also don't 
think that it is necessary to find a defensive weapon in the body 
plan of every herbivore.  There are lots of modern day herbivores 
that have little or no weaponry, and evade predation through other 
means.  And there are many herbivores that have features that could 
possibly be construed as weapons but which are rarely used as such 
(show me a wildebeest impaling a lion or hyena and I'll recant :-)  )


Matt Wedel