Re: Hadrosaur defense.

["Michael" <tons@ccs.netside.com>]

  All we
> can say for sure is that hadrosaurs didn't have any defenses that were
> based on anything that fossilizes. 

Agreed
 No horns, or armor, or high speed,
> or whiptail, or other defensive weaponry.

Do we know the top speed of hadrosaurs.  Whatever it was it was 
likely to be a little less than their main predator.  This is 
speculation ,but based on many mammaliam predator/prey models.  If 
they stay far enough away then usually the predator can't catch them. 
They get an adequate head start.  They didn't have a whiptail but 
their tail had to weigh a good bit to balance their body.  Did they 
use it for defense?  Who knows?  They could have.

Herding isn't an answer --
> ceratopsids also herded, as do modern antelope. 

Herding is an effecient mechanism.  It's more difficult to sneak up 
on a herd.  It's easier to not select one individual to kill in a 
running herd.  Buffalo run lions off at times.  Zebra and topi run 
hyena off. 

  I don't think it's unreasonable
> to think that hadrosaurs had some other defense mode.  Camouflage,
> maybe.  Intelligence, maybe.  Maybe they had skin toxins like a frog. 
> Or sprayer glands like a skunk.  For all we know, they might have used
> those crests to produce carnivore-stunning ultrasound pulses.  
> 
> -- JSW
Your imagination is as good and important as mine.  But they had to 
have at least some defense mechanisms or they would have quickly gone 
the way of the dinosaur.  Oops!<g> 
> 
> 

As always, this is only an opinion, subject to
retraction and recall without notice, and with 
due respect to others opinions.

Thanks,

Michael Teuton MD