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



Monkeys and lemurs are also capable of the motion of flapping and can do
it as well if not better than jaguars, and they both do quite a bit of
leaping about in trees.  Hoever neither extant monkeys, lemurs, or
jaguars have a terribly useful drag mechanism.

It's been suggested (though this may be becoming more unlikely with
molecular testing) megabats are descended from a near-proto-primate. 
Probably the proto-bat had a drag mechanism such as skin flaps on the
hands which later formed true wings.  So if we introduce a drag
mechanism to your leaping lemurs we'd possibly end up with something
very bat-like.
  
the chain of flapping ability plus drag mechanism plus leaping about in
trees all leading to flight does seem to be corroborated by this.

-Betty Cunninghan 


"Jaime A. Headden" wrote:
> 
> 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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