Re: [read and learn]

[archosaur@usa.net]

owner-dinosaur@usc.edu wrote:

> Here's a can of worms I actually would like to open.  On many occasions I
> have heard it suggested that ceratopsians would have turned on their
> attackers and used their horns for defense rather than flee.  Forgive me,
> both those who suggest such a thing do not understand natural selection.
> Let's imagine we have a herd of ceratopsians.  A tyrannosaur shows up.
> Some of the ceratopsians have the "run like hell" gene.  Some of them have
> the "turn and defend" gene.  Now who do you think will be passing their
> genes to the next generation?  Natural selection will ALWAYS favor "run
> like hell."  If the ceratopsian cannot flee, then of course it will defend
> itself however it can.  But it will always go for the flight option first.
> Triceratops horridus did only one thing when it saw, heard, or smelled
> Tyrannosaurus rex.  It ran like hell.
 

I agree. Look at Wildebeest on the savannah and Moose in Canada. When they run 
into a pride of lions, or wolves. Even a lone cheetah or cougar, their first 
instinct is to run. How many times on a nature documentary have you seen a 
wildebeest or Oryx (I believe that's their name.) run headfirst into the open 
maw of a lion. It just doesn't happen. That Wildebeest has to be seriously 
desparate to try such a feat. As for T.horridus they would have done the same 
thing too. Even ankylosaurs would probably try to make a mad dash (probably go 
two feet and then rely on armor. Like turtles do) Regardless of intelligence 
(which is always debateable) the instinct of flight over fight is always there.



> I am less confident about exactly what strategy tyrannosaurs used to kill.
> Tom Holtz and others have suggested that they fall into the pursuit and
> bite category, typified by large canids.  But it is difficult for me to
> envision a tyrannosaur-ceratopsian chase through forest.  I find it more
> plausible that large theropods used a Komodo dragon type strategy, waiting
> along animal trails and lunging out at their prey as it passed by.  They
> slashed horrific wounds, then followed their prey until it succumbed.  I

I have to disagree here. V.komodoensis don't simply wait by game trails for 
some unlucky victim to come by (a common misconception also attributed to 
crocodiles) On the contrary the dragons actively patrol areas that are known to 
frequent prey. The dragons have percieved territories and they patrol them just 
like any tiger or wolf would do. As for the attack it's more of ambush related 
thing after that. Example: A Komodo dragon is patroling it's territory when it 
comes across a wild pig. The pig is eating away oblivious to the danger. 
Meanwhile the dragon is postitioning itself as close as possible for it to 
attack. When the moment is right the dragon bursts from it's hiding place and 
tackles the pig. In this case the dragon easily overpowers the animal and kills 
it dead on the spot. Only some cases like when the dragons are hunting dear, 
would they use the slash and wait strategy. Just for the simple reason that 
deer are a $%%&* to hold on to, and if you let go then they run !
away real fast. So it makes more sense to give them the biggest, bloodiest, and 
most disease ridden bite possible, so that they fall down dead asap.


> believe the reason tyrannosaurs are so gracile is that it does little good
> to slash a ceratopsian and then track down its corpse if someone else gets
> to it first!  This is exactly the problem Komodo dragons face.  
Well the real reason that Komodo's face competition with eachother is because 
they live on an island with a limited food supply and lots of them. So the 
first one to make a kill is bound to not be eating it alone, regardless of 
whether it was killed on the spot or died later on. I believe Tyrannosaurs 
would have faced the same problem too, but probably from other theropods and 
not so much, other Tyrannosaurs (I'm assuming that they also staked out 
territories.)



Having
> cursorial adaptations allows you to move quickly at greater energy
> efficiency, thus reaching your kill before the other tyrannosaurs can.  I
> believe this is what drove selection for cursorial adapations in tyrannosaurs.

> Wasn't that a happy little story?

One for Mother Goose herself.   


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