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Re: My Gr. 9 Science Fair Project: Questions



Stan Friesen wrote:

 From: DRURY <drury@agt.net>

>> 2) My understanding is that crocodillians were predators on
>> hadrosaurs.  I've now read in several places that hadrosaurs are
>> thought to have escaped from theropods by running into water.  This
>> seems odd to me.  It seems a bit strange to run away from one
>> predator by running to another.  Can anyone clear this up for me?

>Yeah - it was a speculation that had little basis in fact.

> Not only did the water have its own large predators (giant crocodile),
> there really is no reason to assume that large theropods could not swim.
> Thus running into the water probably wouldn't get them away from a
> tyrannosaur anyway.

If this is open to speculation, I see reason to speculate that the water
was a good place for duckbills to flee.

Could _T rex_ swim well?  Here's Robert Bakker: "But dinosaurs didn't
produce any swimming predators at all."  

If Cretaceous continents had a lot of broad, shallow waterways, why
didn't theropods produce swimming hunters?  If none became aquatic,
perhaps they never even became good swimmers.

Suppose a giant croc was in ambush at the water's edge when he heard a
three-ton duckbill running toward him.  Wouldn't discretion be the
better part of valor?  After all, a croc killed by accident would still
be dead.

In movies, crocs swim long distances toward human swimmers.  Is that
accurate?  GS Paul said, "Reptiles cannot aerobically sustain speeds
over 1-2 km/h no matter how toasty warm they may be."  If they're that
slow on land, it sounds as if a croc in the water would be pretty slow
once its anaerobic energy ran out.

I don't know how many seconds or minutes this stored energy might last. 
At any rate, it seems that the slower of the dinosaurs would be in the
most danger.  That might be _T rex_.

At least some duckbill genera inhabited conspicuous nesting grounds as
their young grew.  These were apparently not in swamps, but doesn't this
imply that they had methods of standing their ground against predators?

If duckbills were as smart as crows, I think they'd be familiar with the
haunts and habits of local crocs, be vigilant, and pass warnings.  

Don't crows drive hawks and owls from an area by harassment?  Couldn't
duckbills  also have used commotion and tooting to encourage big crocs
to relocate?

Have horses and goats been known to kill snakes on sight?  Humans, dogs,
and cats seem to have that impulse.  If duckbills instinctively stamped
on small crocs, that would eventually reduce the chances of meeting a
big, hungry one.

I think edmontosaurs may have known how to be pretty secure in the
water.

I don't want to perpetrate falsehoods. Have I made many misstatements?

- Stephen Throop