Re: Cretaceous taeniodont

["Tim Williams" <twilliams_alpha@hotmail.com>]

John Bois wrote:

> I am arguing for the following scenario: predators of small mammals may
> have been excluded from some habitats by predation on themselves.  _If_
> bird species and pterosaurs were reduced by predatory birds--and I
> believe the predation hypothesesis explains at least pterosaur dcline
> better than competition--it is feasible that they could also threaten or
> make life miserable for terrestrial (or arboreal?) dinosaurs.

Not sure how/why predatory birds would have been even more of a threat to 
the survival of dinosaurs than the non-avian theropods already were.  Of 
course, predatory birds could attack small mammals from the sky; and they 
were undoubtedly more adept in trees than their non-avian kin were; and they 
could fly away when threatened ...  Still, all these factors must weighed 
against the fact that birds cannot get too big without losing the ability to 
fly.  Are you suggesting that this is why mammals got bigger in the 
Cretaceous, to better protect themselves against predatory birds?


> >A _Microraptor_ or _Sinosauropteryx_ might go for a shrew-sized mammal in 
> a
> > heartbeat, but would baulk at pouncing on a mammal the size of a badger 
> or
> > wolverine.  Of course, the theropods could get bigger too, and so on...
>
> If size gave immunity from predation, why didn't this fuel an arms race as
> it seems to have done in dinosaurs.

How do you know it didn't promote a mammal vs dino arms race?


Tim

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