RE: Early mammals ate dinosaurs

[Tim Williams <twilliams_alpha@hotmail.com>]

Eric Allen wrote:

> What I find interesting is that the _Repenomamus_
> swallowed the psittacosaur without chewing it up.

Says the paper:

"The skull and most of the skeleton of the juvenile _Psittacosaurus_ are 
broken, disarticulated and displaced, [snip]. A few long bones are preserved 
in articulation (Fig. 3), suggesting that the juvenile _Psittacosaurus_ was 
dismembered and swallowed as chunks."

This may imply some kind of buccal processing, or else its claws were used 
to tear up the poor psittacosaur.  In either case, the psittacosaur was not 
swallowed whole.

The paper also says: "In contrast [to hyenas], the enlarged incisors and 
strong jaw muscles of _Repenomamus_ are well shaped for catching prey, 
favouring it as a predator rather than a scavenger."

Again, this does not exclude the possibility that the mammal was scavenging 
in this particular instance.  However, it does suggest that catching and 
killing a live juvenile psittacosaur was no problem for _Repenomamus_.


David Craven wrote:

> Would a further option in this scenario not be that the Protoceratops was
> threatening the Velociraptor nest site and the Velociraptor was defending
> it's territory?
> So the Velociraptor remains the aggressor, but is no longer engaged in an
> act of predation.

Sure, this is possible.  But it's hard to see why the _Protoceratops_ would 
WANT to threaten a _Velociraptor_ nest site.  What's in it for him?

As the saying goes, "When I hear hoof beats I think horses, not zebras".  In 
science, the simplest explanation is probably the correct one.  Not always, 
but usually.  In the above case, the evidence points to a carnivorous 
theropod attacking a similar-sized herbivore as prospective prey.  We'll 
never know what actually happened.  But given the predatory morphology of 
_Velociraptor_, and the poses of the specimens concerned, I think the 
predatory hypothesis is the most parsimonious.



Tim