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Re: hadrosaur tails, a tail of two defences, or a hadrosaur! What a MESS!!!



jamolnar@juno.com wrote:
> 
> Some prey will attack in defense of young.  Many prey (e.g., moose) will
> turn and fight their pursuers (e.g., wolves) after a long run, and if
> they are vigorous enough initially the predators will decide that
> bringing this one down is not worth the risk of injury,  when a weaker
> member of the species can be had.  It all depends on the relative
> physical and hunger condition of the wolves chasing the moose, how many
> wolves there are, how long the chase has gone on, and the physical size
> and condition of the moose.

Sometimes there's even more to it than this.  The relationship between
predator and prey is often complex and subtle, and sometimes more than a
little difficult to figure out.  A study of Isle Royale's wolves and
their prey, primarily moose, indicated very strongly that a moose who
stood to fight when the wolves first came at it was always left alone. 
The only kills resulted from moose that ran.  The same seems to be true
for other big herbivores that wolves go after: if they stand and fight,
they're fine; if they run, they're meat.  In observations of the
now-famous Ellesmere pack, it was clear that in order to successfully
attack a musk-ox herd the wolves _had_ to break the herd's defensive
ring and get the prey animals running.  

However, I'm not sure wolves work very well as an analogy for T-rex. 
Wolves are much smaller than moose or musk-oxen, and can be killed or
crippled by a single defensive stroke of horn or hoof.  At worst, T-rex
was at least slightly bigger than any hadrosaur it wanted to tackle, and
much bigger than most of them.  And hadrosaurs apparently had no
counterweapons as dangerous to a rex as moose antlers are to a wolf. 

So, I dunno what the answer is.  Logic indicates that hadrosaurs had
some fairly good defense beyond herding and high reproductive rate, but
what that was I've no idea.

-- JSW