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Re: DROMAEOSAUR "SICKLE" CLAWS



Ralph Miller III wrote:

> What, then, do <you> think the dromaeosaurs were doing with those big
> claws?

I don't know what they were used for.  I only know that I don't really
find any of the conventional explanations to be convincing.  The huge
foot-claw in dromaeosaurs seems to me to be a case of extreme overkill
in any predatory scenario.  Between foreclaws and teeth, a dromaeosaur
already had as effective a set of killing weapons as any theropod, and
more so than some, like the toothless _Oviraptor_.  If we argue by
analogy with modern predators, then a dromaeosaur hunting alone could
bring down anything its size or smaller with just foreclaws and teeth. 
Dromaeosaurs hunting in packs could take down animals equal to their
collective masses, four or five times the size of a single hunter.  So,
why the big claw if they were already efficient predators without it?

Cats have four claws they use for raking.  Dromaeosaurs had one claw. 
Four claws means the strength of the legs is split four ways.  One claw
means the whole strength of the leg muscles is focused onto one point. 
I can't articulate the argument very well, but there's something about
how focusing more strength onto one point increases the chance of
snagging and doing damage to the claw, and also increasing the clawee's
resistance so that the lone claw actually does _less_ damage than the
four.  So, the single big hind claw may not have been all that effective
as a hunting weapon.  Also, the deeper the claw digs, the more
resistance to pulling it lengthwise.  That big claw would have dug
pretty deep.  What good is a raking claw if it tends to jam or catch in
bones?  You'd wind up with a lotta droms trying to walk on sprained,
wrenched, or dislocated legs. <g>

I suppose one could argue that the big claw developed as a sort of
built-in piton, to dig into a large prey animal's body and hold on while
the teeth and foreclaws did the killing damage.  Unlikely but possible.  

One of the suggestions I've heard that I liked a lot is that the claw
was a sexual characteristic.  That would explain its exaggerated size. 
Have any dromaeosaurs been found with proportionately much smaller
claws, perhaps cases of sexual dimorphism?  

All in all, though, I find that the notion of the foot-claw as a primary
weapon simply isn't convincing.  I think it was used for something else
we haven't yet figured out.

-- JSW