Re: Theropod eating and attacking

[Dann Pigdon <dannj@alphalink.com.au>]

Mark Shelly wrote:
> 
> 
>    Would theropods swallow the bones?   Could they digest the bones or
> would they have to pass them or regurgitate them?  Passing them doesn?t
> look possible to me.  Would the feeding habits change by type or size of
> theropod?  Maybe small prey or fish were eaten whole.  On some theropods,
> hand claws may have been used to dismember the bodies at the joints, or
> scrape meat from bones.  Beaks may take strips of meat at a time.
>    Also, would theropods attack with the head swinging in a sideways arc
> and bite with one side of the mouth?  Or, would they have attacked coming
> straight with the mouth open?  Possibly they attacked from above.  It
> seems
> unlikely that they  choked their prey or tried to bite through the
> backbone
> to kill their prey like cats.  A bite, pull and shred attack like a dog
> would do
> appears better suited for a 4 legged attacker but seems possible.   Maybe
> the
> larger theropods just took a big slashing bite at their prey and waited
> for the
> animal to weaken for a final kill.  I can?t see theropods turning quickly
> like
> cats or dogs when they are chasing prey.  As such, a stealthy approach
> seem
> to be a good way to get close for a final dash.  The pubic bone would seem
> to get in the way if this were the case (although resting on it may have
> allowed
> them to stay ready for an ambush for long time periods).  I don?t have any
> problem with theropods steadying themselves with their hand claws on
> struggling prey while they bit, but I don?t think they would wrestle prey
> off
> their feet.
>    Any comments?
>         Mark Shelly

        I would assume that small theropod teeth were too fragile
to crunch up bones, although they may have swallowed smaller bones
whole. If their digestive systems were anything like that of a
crocodile they would have had no trouble digesting bones (crocs
can ever digest hair and horn). Perhaps larger theropods like
tyrannosaurs could have knawed on bones, I seem to remember a
Tyrannosaurus rex display that was posed in this way. Alternatively
some theropods may have regurgitated bony remains in a manner similar
to owls.
        I would go for the front-on bite. The front teeth of
tyrannosaurs have been described as "cookie cutters" with their
D-shaped cross sections making them distinct from the larger
"fangs" along the side of the mouth. I seem to remember a recent
posting suggesting that Allosaurs may have used a "sabre tooth
cat" approach, slashing with rows of sharp teeth rather than biting
out chunks right away.
        Can't you imagine dromaeosaurs manouvering quickly? But then
again their pubes are different to those in your example.
        As for going for the throat, you are right, theropod teeth
are not shaped for choking but for ripping. When I think of a
theropod attack I imagine a land-based shark rather than a cat or dog.
Great White sharks usually attack from below, often taking one
large messy bite out of the belly of a seal and then backing off
for a while to make sure it was effective. For smaller prey, or
when it is scavenging, it may use a sustained attack. For such large
creatures they seem to be surprisingly cautious. Perhaps theropods
also attacked quickly and efficiently, stood back, and made sure the
initial rush was enough to subdue the prey.
-- 
____________________________________________________

        Dann Pigdon
        Melbourne, Australia
        http://www.geocities.com/capecanaveral/4459/

____________________________________________________