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The "Swipe" of Cats [was Re: bauplan convergence]



Betty Cunningham wrote:

<Leaping about in trees with a symmetrical drag
mechanism (feathers or membranes) leads to gliding.  

However gliders don't flap.  Cats, squirrels, lemurs,
monkeys, lizards, snakes, and frogs don't flap
either.>

  Another reason I mentioned jaguars was that cats
have very mobile forelimbs, like rodents, and maybe as
mobile as primates (ignore the hands). The power
stroke of the bird maybe be approximated by the cats,
with the "swipe", best seen in the tripping action of
cheetahs chasing gazelles. Unlike my previous post on
the arm action of dromaeosaurids (and I'll get back to
that thread, Henri, when I get off work tonight) cats
do not limit their pronation and supination: they
supinate their arms to swipe, and there is no
predilection for resisting force when moving -- the
point is to move the claws into whatever's there,
automatic gripping takes care of the rest. Jaguars, as
I understand, do the same with both arms when pouncing
from above -- so do kittens and housecats, so this is
readily observable by most of the list. This action is
analogous to the "predatory strike" described for
dromaeosaurids and early birds (Ostrom, 1976a,b, 1977).

=====
Jaime "James" A. Headden

  Dinosaurs are horrible, terrible creatures! Even the
  fluffy ones, the snuggle-up-at-night-with ones. You think
  they're fun and sweet, but watch out for that stray tail
  spike! Down, gaston, down, boy! No, not on top of Momma!

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