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about those claws

Hello all,

I hesitated in bringing this up (novice that I am) in hopes that an expert
would mention it.  Oh well.

Birds have a special adaptation in their feet that allows them to perch.
The tendons which control the toes run up the leg and are rather
unelastic.  As long as the bird keeps its leg extended, the toes can move
freely.  If the bird bends its leg, the toes flex because the distance
between the origin of the tendon and the toes lengthens. This allows
perching birds to sleep while perching.  Suppose the dromaeosaurids' large
second claw worked in this manner.  When the animal ran and pulled one leg
up, the second toe would flex and the claw would be pulled downward
(someone mentioned that a dromie might disembowel itself if it kept its
toe in the vertical position while running, made me think of this).
When the leg straightened to contact the ground, the toe could be
raised to the vertical position again to help prevent wear on the
ground.  Also,if the dromaeosaurid attacked something, it might leap and
extend its legs in the air (allowing the claw to assume the "retracted"
position), then when it struck the animal, the impact would bend the leg
and for the claw downward and into the prey.  With its initial momentum
gone, the dromie would begin to slide down the side of the prey animal,
dragging the claws (this would work better with the "all toes in the kick"
theory). This assumes, of course, that the dromie was hanging on and/or
attacking with its mouth and hands.  

Well, that's my two neurons' worth.  I expect the flames to start any
time.  Have a wonderful evening.