Re: Crocodilian vs Avian looks

[Waylon Rowley <whte_rbt_obj@yahoo.com>]

To David Marjanovic:

> Yes, they don't chew. Sauropods didn't have cheeks 
> either.

Iguanas don't chew? I've owned 2 large iguanas, and I
must say that they DO chew. Not cow-like chewing, but
chewing nonetheless. They grip the food, and tear off
chunks, slicing them until the leaf is soft and easily
swallowed. BTW, aren't the teeth of Iguanas similar in
shape to Iguanodon? 

> > Maybe they had stiff lips that slid past
> > eachother to help keep food in,
> but when the dinos opened their jaws in chewing...

Yes? What would happen? I imagine these lips would be
fairly wide, so that they never slid over eachother
the wrong way....kinda like scissor blades.

> Tongues are inside, erm...

Yep. We position our food with our tongues, so in
addition to the aforementioned lips, they could be
quite useful. Back to iguanas. My beloved pet would
often use his sticky tongue to retrieve fallen plant
matter, so Protoceratops could do the same with its
tongue (theoretically).   

> Slicing is still close enough to chewing that I'd 
> say that much would have fallen out of their mouths
> if they didn't have cheeks.

Iguanas slice their food (don't forget the Soloman
Island Skinks as well) and they have no cheeks, so I
doubt cheeks are required for a herbivorous diet in
dinos. Another thing: The "vascular foramina" are
described by Currie in his Acrocanthosaurus paper as
branches of the medial ethmoidal nerve and subnarial
artery (but the artery probably passes through the
subnarial foramen). This got me thinking about why
theropods would have such sensitive snouts. Well,
(deep inhalation) I believe the animals were keeping
track of nest temperatures and adding/removing
vegetation to keep the nest in an equilibrium. By
sticking their snouts on/in it they could monitor the
fluctuations. When the babies (neonates? chicks?)
began to hatch, the mother would sense vibrations
within the nest as they tried to struggle free of
their eggs. This would prompt the mother to aid in
freeing the hatchlings by removing excess plant
material as modern crocs do. Now, this isn't so wild,
but now i'm going into some major speculation. Once
the babies were free, the mother would scoop them up
in her mouth like a crocodile to help keep them warm
(I would think a full grown Giganotosaurus could hold
her entire clutch/brood in the mouth). Once the babies
used up what was left of their yolk sacs, they would
need to be fed. So, the hatchlings would peck at the
margins of their mothers snout and jaws (they are
still inside the mouth at this point) and the mother
would regurgitate food into her throat sac (kinda like
a lizard dewlap) where the babies would feed from
their first few days of life. Once they had grown to
the point where momma couldn't fit them all in her
huge jaws, she would begin taking individuals and
smaller groups to kill sites where she would rip off
small chunks of flesh from the carcass. The baby would
then begin eating the flesh caught between her teeth.
Finally, the hatchlings would be large enough to start
tagging along with mom and eventually join the family
group. Personally, I like this idea....it's kinda like
a transition between croc and bird nesting behavior. 
Any thoughts/criticisms?
 

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