Re: a question for the tyrannosaur experts was: How Did Hadrosaurs Survive?

["Tim Donovan" <msdonovan66@hotmail.com>]

> From: John Bois <jbois@umd5.umd.edu>
> Reply-To: jbois@umd5.umd.edu
> To: Cliff Green <dinonaut@emerytelcom.net>
> CC: dinosaur mailing list <dinosaur@usc.edu>
> Subject: Re: a question for the tyrannosaur experts was: How Did Hadrosaurs 
> Survive? Date: Mon, 28 Oct 2002 07:21:03 -0500 (EST)
>
> On Sat, 26 Oct 2002, Cliff Green wrote:
> >     HEY! all you list Theropod experts. Can any of you be of assistance?
>
> This ain't me...but here's my perspective anyway: duckbills may have been
> faster/more manueverable than _T. rex_.  But, during nesting season (2+
> months or so in duration) these attributes would not have helped much.  We
> see duckbill nesting colonies and this gives us a clue as to what might
> have been going on.  Assuming _T. rex_ could access nesting grounds, what
> was the function of the colony--why nest in a colony?  Three
> (main?) reasons are possible: limited substrate (unlikely), info sharing
> (unlikely since duckbills couldn't really forage over a wide area in a
> short time), and defense.  If defense, then the predator must be one that
> the duckbills could supress--to some extent at least.

 Maybe hadrosaurs nested in colonies so that they could take turns guarding 
the nesting area while others temporarily left to forage. I doubt they 
banded together for protectin against tyrannosaurs, which could also have 
been gregarious and were certainly better armed. AFAIK, there is no evidence 
for tyrannosaur attacks on hadrosaur nesting areas. Troodont teeth have been 
found in association with hadrosaur nests. Presumably they preyed on 
juveniles but tyrannosaurs needed larger prey.




 So, my guess is
> that they had some sort of group defence--not too organized--in nesting
> season.  In other times I would guess it was a
> sometimes-you-win/sometimes-you-lose chase and catch the young, weak, or
> old.


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