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Re: Dromaeosaur "sickle" claws



From: Ralph Miller III <gbabcock@best.com>

In my opinion, the highly curved, blade-like "sickle" claw must have been
able to rake through flesh.  Do swords or scalpels require serrations to be
effective slicers?  

I have read suggestions that dromaeosaurs might have jumped onto the backs
of larger animals, clinging with their hands, and raking with their
terrible claws.  I also recall reading Jim Kirkland's notion that
dromaeosaurs would stand on one foot or jump, like a cassowary, and kick
their prey to death.  (I should point out that in his post he was adopting
Ken Carpenter's position that dromaeosaurs'  unserrated pedal claws were
made for stabbing, not slicing).  Of course, we can't prove exactly what
was going on.  Probably a variety of methods were employed.  I would like
to propose another possible modus operandi.

Consider the "fighting dinosaurs" excavated by the 1971 Polish-Mongolian
expedition at Toogreeg in the Gobi desert.  Here we have an articulated
skeleton of _Protoceratops_ locked in mortal combat with the dromaeosaur,
_Velociraptor_.  The ceratopid is clamping down on the forearm of the
dromaeosaur.  The dromaeosaur, in turn, is grabbing the ceratopid by the
skull and has its left foot lodged into the ceratopid's throat.  As one
would expect, the dromaeosaur is preserved lying on its side.  This may be
a case of preservational bias (the dromaeosaur has a body that is quite
narrow laterally) or it could be that the fight occurred down on the
ground.  The fossil has not been fully prepared in the photograph at hand,
so the exact pose of the ceratopid is unclear.  But it seems to me that a
parallel could be drawn here with one of the attack strategies of extant
felines.

House cats will pull small prey to the ground, cling with their forelegs,
and rake the prey's underbelly with the claws on their hind legs.  (This is
also the classic "catfight" mode employed during intraspecies conflicts
between cats.  So unless you're a nursing kitten, you are warned to avoid
stroking the  cat's abdomen while it is lying on its side).  I have often
seen my cat, Pippin, chase down a toy mouse, grab hold, drop down on her
side, and have at it with her "sickle" claws.  Interestingly, Mark
Hallett's illustration of the fighting dinosaurs on page 185 of the book,
_Dinosaurs: A Global View_, depicts the ceratopid four-square on top of the
dromaeosaur, but that is not the pose seen in the articulated fossil.

Anyone interested in theropod action simply must read Gregory S. Paul's
_Predatory Dinosaurs of the World_, particularly the chapter entitled:
"Lifestyles of the Big and Powerful, and the Small and Fierce, too".  He
has covered much of the same ground as we have been retracing on this list.
    

Ralph Miller III <gbabcock@best.com>

"God gave Man the Cat so that He might feel the fur of the Tiger without
also feeling Her teeth."

.