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Dan Bensen wrote:

<<Perhaps 'carnivory' and 'herbivory' are merely
different gradations of omnivory.>>

Samuel Barnett wrote:

<Well that sounds feesible [refering to Dan Bensen -
after all if predator and scavenger are different
gradations of both (is there one word for predator and
scavenger combined?)>

  Yeah, "carnivore" or "meat-eater."

<It'd make sense that the two extremes of omnivory
would be the case too.>

  There's no extreme of omnivory: you either eat one,
the other, or both, but the "habit" of eating is
different from the biological and physiological
adaptations to one, the other, or both.

  Carnivores have short digestive tracks, really nasty
gastric acids for proteins breakdown, large slashing
and shearing teeth, and relatively hooked
food-manipulating devices, being either teeth or
claws, etc. --- Hypercarnivores reduce their dentition
to strict shearing, slicing, and piercing forms, with
reduction in numbers, to achieve what we see in felids
and nimravids, though more so in the former than in
the latter, as well as exceptional development of
"sawing" actions in the jaws. --- Hypocarnivores, such
as bears and dogs, appear closest to herbivory in many
forms, and are often regarded as omnivores, but
anatomy would appear to regard them as
[hypo]carnivores; they have a sort of midway dentition
between flat molars and shearing molars, more shearing
in dogs, but more flat in bears, and especially flat
in ailuropodids[?] [pandas].

  Herbivores have relatively long digestive tracks,
often with additional intestinal extensions called
cecum for fermenting, gizzards or similar pre- or
re-digestion organs (multi-chambered stomachs in
ruminants do the trick) and rough, highly developed
but level-topped teeth with several shearing ridges
rather than a single edge, and a strait chopping edge
in the incisors and other pre-canine teeth. --- Hyper
herbivores such as horses, cattle, and elephants
reduce dentition to the grinding teeth, molars and/or
premolars and such modified into near-identical form
[elephants further modify the form by loss of most
teeth]. --- Hypocarnivores like deer, camels, pigs,
and such still retain canines, postcanines, precanines
not developed into flat teeth but as "tusks" and as I
suggested privately a few months ago to one of our
number, it wouldn't be a big step for a hypoherbivore
to descend into regular meat-aquisitive habits, as
pigs readily shows signs of. Entelodonts are an
excellent example of extinct suimorph artiodactyls
that descended into this form of primary carnivory
from an herbivorous ancestry, at least as far as I can
tell by phylogeny.

  Omnivores are the mid-range, like blending
hypocarnivores and hypoherbivores -- take a dog and
pig and cross 'em for a physiological transition.
Ecologically, we seem to represent an easy example,
but this could be simple bias on my part to look for a
proper example outside of *Homo*. Anyway, dentition
consists, as any dentist can tell you, of flattened
sharply cusped molars (semi-bladed), almost
spoon-shaped cuspids, and premolars, and semi-conical
bicuspids and canines. This heterodonty as seen in man
seems to make proof of Greg Paul's argument as
presented by Darren Naish, and the closest known
example in dinosaurs is heterodontosaurids;
hypoherbivores by extension appear to exist in the
form of protoceratopids, archaeoceratopids,
leptoceratopids, psittacosaurids, pachycephalosaurs,
and the less iguanodontian-like "hypsilophodontians"
like *Bugenasaura,* etc.; hypocarnivores could be
represented by such leaf-toothed animals like
troodontids, therizinosauroids, *Eoraptor*, etc.;
hypercarnivores would be all standard theropods with
exception of ornithomimosaurs and oviraptorosaurs, who
lack defining dentition, but short guts
[hypershortened, actually!] appear to indicate
carnivory; and hyperharbivores would be pretty much
all dryomorphans; the odd teeth of thyreophorans would
appear to represent the hypoherbivore model, with
relatively "blade-like" teeth, but everything else
suggests hyperherbivore.

  Such things as folivory [under hyperherbivory] and
frugivory [under hypoherbivory?] both involve
adaptations of teeth formed into chopping units (the
former) and piercing units (the latter) as exemplified
by sharp-beaked birds and extant [*Bradypus* and
*Choloepus*] sloths respectively. Formicivory [under
hypocarnivory?] is represented by blunted and reduced
or totally absent dentition and the added condition of
additional enzymes and bacteria in the gut to process
the ants and termites and such (pangolins and
anteaters are examples, and therizinosauroids have
been proposed as formicivores -- Rozhdestvensky,
1969?). Folivores and formicivores require extra
enzymes, and folivores and frugivores require long
guts for processing, though Candadian geese (*Branta
canadensis* to Darren) _very_ quickly process grass in
huge flocks, leaving by little white slicks as they
_march_ over fields in minutes, defecating as fast as
they eat.

  It's physiological considerations like these that
made me want to resist being shy and step up to the
physiologists like Reid I saw at SVP. Damn me!

  Anyway, I hope I didn't get anything wrong, or
missed a consideration.

Jaime "James" A. Headden

"Come the path that leads us to our fortune."

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