Re: attack on dinosaur--horrific video

[David Marjanovic <david.marjanovic@gmx.at>]

> > I will just bring up *Repenomamus giganticus* again, which must have 
> > ushered in the Great Barremian-Aptian Boundary Mass Extinction, except it 
> > somehow didn't.
>
> Anne Weil discusses this anomally, saying research is going on trying to 
> find out if dinosaurs at that place and time were smaller than usual. 
> Certainly there are selection pressures for being large or small.  What 
> were they in each case?  Dinosaurs were not smaller in the late K.   Also, 
> _N. improvida_ and _C. magnus_ were very different creatures from _R. 
> giganticus_.  I don't know that much comparison is afforded--other than 
> the interesting question of relaxation on size constraints enjoyed by both 
> clades, likely for different reasons.

I repeat: By your logic the two species of *Repenomamus*, not to mention 
*Gobiconodon*, triggered a mass extinction among egg-layers. How is it 
possible that they didn't? If the answer lies somewhere in "very different 
creatures", then please elaborate. Remember the specimen of *Repenomamus 
robustus* that has *Psittacosaurus* as stomach contents, so we know what it 
did, and we also know that *Psittacosaurus* went on to survive for the rest 
of the Early Cretaceous (some 25 million years).

> > Not even the crocodiles died out.
>
> ??

Crocodiles nest on unprotected riverbanks, with themselves as the only 
protection. And indeed, their nests often are raided in the middle of the 
day. How is it possible that they are still with us?

> > Are you certain that ground-nesting birds are generally night-blind?
>
> I know an attended ostrich nest is practically immune from predation in 
> the
> day--but that, if discovered by black-backed jackals, they are invariably
> destroyed at night, i.e., the ostrich can defend effectively in the day 
> time
> but not at night.

That is one. I was talking about "generally".

But I don't think this will lead us anywhere. With fossils, all evidence we 
have is the relative size of the empty eye socket...