Re: New dinosaur paper: Ankylosaur tail club smacking

[Tim Williams <tijawi@yahoo.com>]

Andrew Farke <afarke@gmail.com> wrote:


> I've briefly blogged about the new
> ankylosaur function article at the
> Open Source Paleontologist:
> 
> http://openpaleo.blogspot.com/2009/08/new-paleo-paper-in-plos-one.html


As stated in the abstract, "Large knobs could generate sufficient force to 
break bone during impacts, but average and small knobs could not".  But I 
wouldn't have thought that average and small knobs were therefore 
non-functional as defensive devices against predators.  It would not be 
necessary for the ankylosaurid to debilitate the predator by breaking bone, but 
simply to warn the predator off.  

The predator wouldn't *know* that the swinging tail club of a smaller or 
mid-sized ankylosaur would not break its ankle.  The fact that the blow would 
hurt (and probably quite a lot!) is reason enough to avoid it.  If the predator 
was struck by an undersized tail club, the pain inflicted by the blow would 
tell the predator that there is the *potential* for a debilitating injury (even 
if, biomechanically, there isn't enough impact to smash through bone).  The 
predator may have even have witnessed (or experienced itself) a blow from a 
large tail club to be aware of the consequences.  

In other words, for ankylosaurids as in politics, perception is more important 
than truth.  If a predator perceives a tail club to be dangerous (because in 
larger ankylosaurids it really is), then it will avoid it, for fear of 
incurring a crippling injury.


Cheers

Tim