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Re: Sabertoothed Carnassials in Pandas?
More on carnassials:
Dogs and cats draw the inner edge of the upper carnassial tooth (premolar #4)
against the outer edge of the lower carnassial tooth (molar #1) when slicing.
They have cylindrical jaw hinges to keep these edges lined up; they cannot twist
their mandibles laterally (as ungulates do). By acting against each other, the
blades are self sharpening. Dogs have functional crushing molars behind the
carnassials; cats do not. So dogs can chew with their molars, but cats can't.
The early carnivore, _Myacis_, had short shearing surfaces on its carnassials,
the cutting edges were aligned diagonally with respect to the dental row, but
advanced carnivores sport carnassials with long cutting edges which are in line
with the dental row.
See pages 62 - 64 in R.J.G. Savage & M. R. Long, 1986, _Mammal Evolution: an
Illustrated Guide_, ISBN 0-8160-1194-X (out of print).
-- Ralph W. Miller III firstname.lastname@example.org