herbivore <----> carnivore

[Bart Singer <singer@tab00.larc.nasa.gov>]

Scott writes:
> I don't want to dwell on this topic, so this will be my last comment. It seems
> to me that diet is so strongly programmed in a species instinct that it would
> starve rather than try some other food. For example, I have heard that this is
> true of Koala bears. They will only eat Eucalyptis leaves and NOTHING else. If
> the supply of Eucalyptis dwindles, Koalas will starve, even though there is
> plenty of other plant life around. If they won't even try another type of 
> leaf,
> then it certainly seems like a stretch that they would turn carnivorous.
> 

[ other stuff deleted]

> I do accept that some animals are omnivorous (bears, humans, etc.) and perhaps
> many (or most) pre-Mesozoic animals fit the bill. But from the Jurassic period
> on, I think the dinosaurs would be too specialized in their diet to change.
> Perhaps as specialized as Koalas, so that eg. each genus or species of
> herbivores would have evolved for each particular plant type. Of course,
> carnivores are not as particular :)

I think that extremely specialized diets are more the exception than the rule.
I've seen dogs and cats apparently enjoy eating vegatables.  I also once 
owned an African Grey Parrot.  The bird is well adapted to a vegetarian diet;
parrot beaks are great for cracking nuts. Yet my bird would eat almost
anything: pizza with pepperoni, ice cream, even chicken.