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Re: Mammals preying on giant azhdarchid pterosaurs!

On Mon, 22 May 2000, Ahmed al-Mahasa Sha'ad wrote:

> > > What about the many  marine crocodylians in the Mesoxoic?? What about 
> >the
> > > mosasauyrs and plesiosaurs and icthyosaurs (which did not lay eggs)!!
> >
> >No clue.  How does this relate?
> It relate becuase  eggs of marine reptiles would be as  hard to get to as 
> the eggs of amphibius crocodyles.  Icthyosaurs did not lay eggs at all. but 
> these marine reptiles are all extinct too -  like dinosaurs.

We know the nesting environment of extant crocs.  We don't know about
marine reptiles.  However, if they were oviparous, they certainly could
not handle themselves on land as well as crocs do!  Therefore, if they
laid eggs in places where mammal and/or birds could reach them, those
predators would have less to fear from them.  They would be more likely to
become extinct.

> Why did these egg-eatiung mamals not eat birds eggs too - they could climb 
> trees.

Birds exert much energy and behavior in avoiding predation.  But,
according to some researchers, they do avoid it because of their small
size and the ability this gives them to conceal their nests from
predators.  This,
at least, is a respected opinion.

> And for dinosaurs - cannot the parents defend their eggs from little mammals 
> - specialy if the mother is sitting on them? Perhaps the mamal could steal 
> one egg or two if they are brave - but ALL eggs!!!

Rheas abandon their nest after discovery.  Ostrich, too (I think).  Once
discovered, the hard work is done.  I think the case for predation on
larger animals'eggs is easier to make.  This is especially true for
nocturnal mammals against diurnal dinosaurs.  Dinosaurs may well have had
an instinct which said: "Whatever you do, don't move around your eggs at
night time."