Re: The absurdity, the absurdity (was: Cooperating theropods?)

["Larry Dunn" <larrydunn@hotmail.com>]

From: Chris Campbell <sankarah@ou.edu>

>> Surely you're not saying that cheetahs and wolves are basically the 
same
>> animals because they both suffocate their prey?
>
>No, I'm not.  I'm saying that what they can go after is limited by the
>fact that they have a given method of killing their prey.  They have to
>be able to a) chase it down and b) apply that strangulation/suffocation
>bite.  Deinonychus had a totally different method of killing its prey,
>so the constraints we see in modern animals just don't apply.

This is presumably based on the presence of one large claw on each 
hindlimb.  But that does not follow, because the large claw could have 
been used to disembowel small animals or to sever the arteries of 
somewhat larger animals as may have been happening in the Tugrugeen 
fossil.

>> Why's their "potential prey" so big?  
>
>Assumming we're talking about Tenontosaurus, here.

Yes, but why assume active predation on Tenontosaurs?  Only a few 
species of mammalian predators hunt animals larger than they are.  All 
other terrestrial vertebrate predators hunt smaller animals with great 
success.  Does the single large claw on each foot throw out the rules?  
Particularly with respect to an animal which fairly clearly did not have 
adequate intelligence to behave cooperatively with other members of the 
species?

>> There's no comparison between the forelimbs of a felid and the
>> forelimbs of a dromaeosaur. 
>
>I never said there was; I just noted that some extant predators don't
>have any trouble holding onto a prey animal, even while it's moving and
>bucking around.

Yes, and that's because their forelimbs are suited for it.  Unlike those 
of Deinonychus.

>>catch a hold with those extremely avain forelimbs (somehow), 
>
>Forelimbs with sharp claws.  Again, see GSP's illustration in TDE.

They could have had razors issuing from their forelimbs and that doesn't 
change the basic fact that dromaeosaur forelimbs weren't really suited 
for grasping and holding on to a moving animal.

>>Probably draw the attention of the tenontosaur so it could turn around 
>>and squash the pipsquak who had such nerve as it fell off.  As you 
know, 
>>herbivores don't take being preyed upon lightly.
>
>Yeah, but unless they're Buffalo they usually can't do much about it. 

Buffalo are not the only predators that defend themselves successfully.  
Many do.

>Also notice that predators are pretty good at taking punishment; we've
>all seen the Discovery channel shows wherein a lion or cheetah attempts
>to tackle a wildebeest alone, gets tossed all over creation, and 
finally
>gets thrown off, tossed, trampled, or whatever only to get up 
bewildered
>and wiser but otherwise unharmed. 

Predators have to be in top shape to hunt successfully.  Small injuries 
can often be fatal to them, let alone major ones.  A lion whose jaw has 
been broken by a zebra was essentially killed by the zebra.

 So the Deinonychus leaps onto the
>Tenontosaurus, gouges it with the big claw, hops off to scamper away
>while the Tenontosaur turns to deal with its tormentor, only to set
>itself up for a similar attack from the other side.  Heck, this 
wouldn't
>even require any coordination; just pack members tackling whichever 
side
>didn't have a bucking head attached.

The scenario you describe takes a lot more coordination than most 
*mammalian* predators employ!  And I'm not as enthusiastic as you to 
adopt such a meat-on-the-table view of a large herbivore.  Because they 
don't eat meat doesn't mean that they're not aggressive, especially in 
defending themselves.  Even assuming for the moment that the killer 
raptor rationale for the dromaeosaur/deinonychus site is correct, it 
seems that tenontosaurus was prefectly capable of defending itself.
  
>Tell that to wildebeest.  Five hundred thousand are born every year in
>the Serengeti, and the population is quite stable.  That means five
>hundred thousand, out of a population of a *million*, die off every 
year
>during the annual migration.  

You're agreeing with me.  All animals suffer massive attrition away due 
to a variety of factors.  Lions lose many of their cubs too.  The odds 
are against young and adult animals of every species.  So why then would 
dromaeosaurs engage a prey species capable of killing three of those 
precious few survivors in a single feeding event?  Were there no lizards 
to eat?  Smaller dinosaurs?  Mammals?  Seems rather fantastic to me.
 
>And
>let's face it, if they weren't terribly bright and didn't use
>sophisticated methods to hunt, how much training do they need?

Assuming these things, they presumably did what other small, 
not-very-bright predators did (and do) -- they hunted alone and ate 
things smaller than they were (large claws notwithstanding).  Hunting 
animals larger than you requires both intelligence and sophisticated 
hunting strategies.

>>We can't want killer raptors so badly that we lose sight of this.
>
>Agreed.  And we can't want to tear down the image so badly that we lose
>sight of other options.

"Other options" should not include basically describing an animal 
starting with a tabula rosa because it has large claws on its hind legs.  
This had led you to invent a creature that hops atop it's prey's back 
and slash with hindclaws notwithstanding the unsuitability of its 
forelimbs for such grasping; an animal that sort of cooperates without 
cooperating, incidentally adopting (systematically!) an incredibly 
elaborate strategy-that's-not-a-strategy.

Larry

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