Re: possible ceratopsian feeding behaviour?

["Jaime A. Headden" <qilongia@yahoo.com>]

Stephan Pickering (stefanpickering2002@yahoo.com) wrote:

<Unless I am mistaken, there was foliage of variable height during the
late Cretaceous, and ceratopsians growsed/grazed on it. In other words,
they were growsing grazers and grazing growsers...herbivores.>

  Grazing refers almost soley to cropping grass or short ground-covering
vegetation, as in ferns or the like, close to ground, not just low-lying
vegetation like small bushes. The trick here is the type of plant, being
highly silicaceous modern grasses require specialized dentition
(hypsodonty) with flattened, multi-lophed crowns for shreading bitten
matter. Similarly, the front of the jaw and the teeth therein are largely
trnasverse in orientation, allowing cropping to occur. An animal with a
pointy snout cannot crop ground vegetation unless it held its head
sideways to it, which it both impractical (risky to survival and
excessively wasteful of evergy and time) as well as anatomically
impossible -- it would have to lie down to do this in any event, and
grazers must keep moving to eat ... silicacous grass does not offer much
in the way of nutrition. Ferms do not occur in large enoguh patches the
modern world enough to infer they could in any extinct ecosystem, and no
fossil discoveries support large swaths of group big enough to support
several multi-ton animals without proving completely ineffective at
managing a biomass. Grass is silicaceous (resistance), fast reproducing
and growing, permitting it to be a viable food product, which is why in
the Miocene grasslands became so prevalent.

  The jaws of ceratopsians are not designed for grazing, and this must be
taken into consideration when inferring their ecology. There is a long,
cropping/crushing beak in front, and a set of ample shears behind
supported by a massive set of jaws, indicating ceratopsians regularly took
on food that required much more mechanical effort to harvest than it did
to process; the shears imply ability to render into sections, but not
orally process as do grazers. Ceratopsians most likely had no means to
process their food in their jaws. There are no extant large herbivores
which live in closed, forested environments which have such a dentition
like ceratopsians; this indicates at least that there are no extant
analogues, unlike the so-called ungulate/hadrosaur analogues worked on by
Janis and Caranno (together and separately).

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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