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Re: The uses of sickle claws



At 10:16 AM 20/09/97 +1000, you wrote:
>       On second thought (see a previous post on the same topic),
>I'd say it was just as likely that V.mongoliensis was caught in
>the act of robbing a nest of eggs/hatchlings.

Dromaeosaur teeth seem like WAY overkill for egg eaters.  They may not pass
up a free lunch, but I doubt that they only (I know you are not suggesting
this) looked for the eggs.  Mmmmm..... hatchlings..... reminds me of several
Larson cartoons.

> Just because it has
>an impressive array of foot weaponry doesn't mean it ever used
>them while hunting. The musk deer has long sharp canines, but is not
>carnivorous. The same goes for gorillas and giant pandas. Foot claws
>may have been used for climbing, or for ritual displays (the musk
>deer again), or for holding/tearing a carcass (isn't the shape of
>dromie foot claws similar to the curve of modern raptor beaks?)
>, or purely for self defence (cassowaries).
>--
First of all, are you suggesting that dromaeosaurs were not carnivorous?

Considering the size of some of the larger dromaeosaurs (such as Utahraptor
and the undescribed late Cretaceous form from Mongolia), I am not so keen on
the tree climbing idea.  Considering how crusorial the dromaeosaurs apear to
be, I think that this could be a dubious line of behaviour for them.
Velociraptor was from an arid area, so I don't see much tree climbing in its
environment.  It still maintained the weapons.  They might have managed to
get up a tree, but then again, so do some dogs.  I saw Larry Martin (I know,
not a good name on this list sometimes) talk about the ability of
dromaeosaurs to climb trees.  He thinks they were too deep and narrow to
have their body mass work for tree climbing.  I am inclined to agree with him.

I don't quite follow your argument.  As well as display, these features
(specifically canines) are used in intraspecific combat.  They are
extensions of already existing teeth.  Humans have the remnants of these
canines (much reduced).  These claws (and the leg muscles that evolved to
run them) and the joints they attach to are HIGHLY specialized.  They are
designed to put great force over a wide angle of motion.  The second toe is
designed to be held in unusual positions.  The other claws are sharp as well
(enough that a specialized toe would not be needed), and would seem overkill
if we are using them for intraspecific combat.  Roosters have spurs, but
there is nowhere near the specialization in there entire body plan.  Often,
only the male of the species has the huge -fill in body part here- for
combat or display.  Find me a dromaeosaur with no eveolved second toe and I
will change my story.

My final argument for the adaptation of the second toe is the fact that it
is seen in juvenile specimens (the one from Montana).  Most display features
are only achieved in adulthood (even in other dinosaurs, ie tyrannosaur
rugosities, duckbill crests, ceratop(s)ian (hey, I'm allowed to cover my
butt) horns and frills).  They seem to be needed from a very young age.  It
had to be necessary for survival, or they likely would have atrophied.

Wow, this got out of hand.  Sorry for the length.

Darryl            <dinoguy@interlog.com>
Visit my webpage at:
http://www.interlog.com/~dinoguy
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"Genetics explains why you look like your father, and if
you don't, why you should."  (anonymous)
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