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Re: CRETACEOUS VARANIDS



Toby White wrote:
> 
> Darren Naish said:
> 
> >got virtually no mammalian carnivores). This theory, nice as it is,
> >has been invalidated by the large number of Australian marsupial
> >carnivores described in recent years: new dasyuromorphs, carnivorous
> >macropodids and thylacoleonids a-plenty.
> 
> I get the impression that mammals change dietary habit quite easily, whereas
> dinosaurs (AFAIK) have made the transition only twice, both times from
> carnivore to herbivore (unless one includes birds).   Furthermore, I've
> never heard of a dinosaurian omnivore.  Perhaps they exist, but it doesn't
> seem to have been a common habit.  Is there a simple explanation for this
> pattern?
> 
>   --Toby White
Mammals have an advantage in this by virtue of tooth design.Mammals have
a variety of tooth shape in their mouths...molars (for grinding),
canines(for puncturing), etc..This makes it a bit easier to move from
one end of the diet spectrum to another if they feel the evolutionary
"push" :)