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Re: Experts had thought only herbivores hunted in packs...



Larry Dunn wrote:
> 
> --- Stephen <stephenbowden@home.com> wrote:
> 
> > Phil Currie told the BBC: "It seems to me that we
> > have very convincing
> > evidence that large meat-eating dinosaurs formed
> > these social groups
> > where the young and the old worked together, hunted
> > together and lived
> > together."
> 
> On equally good evidence, Phil Currie also opines that
> agile young tyrannosaurs herded prey into the waiting
> jaws of cumbersome adult tyrannosaurs.
> 

Thats nice of them! 

I agree. The pack-hunting evidence was extremely flimsy. Any number of
bone-beds consisting mostly or entirely of large theropods fail to
constitute evidence of pack behaviour. 

Far from being evidence that they "worked together, hunted together and
lived together" it is, at best, evidence that they died together. If we
reject the predator trap idea and the geology suggests that it was not a
sandbar style post-mortem accumulation, then what killed them? Grief?
One member of the pack died and the rest keeled over in sympathy?!!! Or
is he suggesting that they returned their dead to a theropod graveyard? 

Or perhaps an Argentinasaurus rolled over and flattened them during a
pack hunt ;-)

The absence of herbivores doesnt really mean anything. All it takes is
one dead animal - a herbivore we haven't found yet or a theropod which
wandered in by chance. After that, the smell of decay would soon bring
other carnivores in. 

Predator traps dont have to be tar pits. I remember seeing film of a
modern day death trap in which toxic gases collected in a low lying
area. One animal wandered in and was overcome. Before long every
predator and scavenger in the area is attracted by the smell of carrion,
with disastrous results - the local herbivores probably make themselves
scarce when the predators begin arriving. 

In Cretaceous times what would be the result? - a theropod bone bed -
with no evidence of a La Brea type predator trap and few if any
herbivore bones.

It seems at least as likely as invoking some catastrophic external event
to kill an entire pack of theropods in one location.