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Re: Deciduous horn?



>There is a very quick way to tell the difference between an animal with
antlers and horns.  Since antlers are dropped every year, there will be no
central, bony horncore.  For an example, take a look at the skull of a
white-tail deer buck; there are cylidrical (sp) projections behind the eye
(these don't mimic the shape of the antler), the flat tops of these are the
base for the antlers.  For an animal with a true horn, like a cow, the bony
part of the horncore will mimic the shape of the horn.  For ceratopians,
the latter model fits, so they didn't have antlers, they had true horns.
>Rob Meyerson

Which, I am afraid, does not answer the question.  Pronghorns have true
horns, but shed the outer sheath annually.  More to the point, perhaps,
birds may shed and regrow outer keratin layers such as the ramphotheca of
the bill as part of the molt process.  I see no reason why horned dinosaurs
might not have shed the outer horn sheath occasionally even if the bony
core remained in place, though I have no evidence on the subject.


--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court                 
Mississauga, Ontario, Canada L5L 3W2          Internet: ornstn@inforamp.net