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Everyone's discussing bird origins...



At 04:41 PM 9/26/96 -0500, Mickey wrote:

>[ Instability frequently accompanies high maneuverability.  Look into
>  the designs of the F-16, F-117 and most of all the F-22.  Sorry to
>  keep throwing comments into other people's messages, but it's faster
>  for me this way and you guys are keeping me busy! -- MR ]

        Ok.  I kinda have to bottle up some re:s here so tat you have fewer
messages to review, is that ok?
        You are absolutely and 100% correct, and I did consider this (I was
thinking mostly of the X-22 myself, what my father calls the "Shake-apart
Special").  Do we have _any_ evidence of dynamic instability (I believe that
this is proper nomenclature) in any animal?  And I'm not just talking
boundary-layer instability like in shark dermal denticles, I mean real,
honest to goodness instability?
        Considering that the aircraft in which this is a feature, the entire
flight regime is closely monitored by a bank of computers ("So, Dr.
Strangelove...") to prevent the aircraft from going wildly out of control, I
personally doubt that such a feature would develop to any great extreme on a
bird.  Besides, I can't envision a braking motion which would need to be
combined with zippy maneuvering.  On the other hand, if a small theropod is
running, gets unstable, and falls, hey, it's not t-rex!

Wayne A. Bottlick wrote:

> In the example of owls and eagles, there is a significant difference from
>the proposed flightless (at the beginning, anyway) biped:  upon catching the
>prey with their talons, these extant predators use their flying abilities to
>return to their perch, or nest, whatever; they still have locomotion.  In the
>proposed predecessor, what does he do immediately after the pounce?

        Just exactly the same thing a dromaeosaur would do after jumping
into te air to use it's sicle claw (would someone please tell me how to
spell that?  Dyslexia kills, man...).  Nothing more, nothing less.
        WARNING:  Pure speculation ensues:  I really don't see how this
presents a problem.  Perhaps you are thinking about prey that is too small.
I am thinking, say, one or two chicken-sized dromaeosaurs drop on a
sub-adult protoceratops.  One drops onto the back and slices down the sides,
holding on with it's grasping claws.  The ceratops bucks, the dromaey falls
off, the other drops.  That ought to be enough...  If they can slice it up
fast enough, they can even run away carrying bolts of meat in their hands
for consumption later.  

Corey Gross wrote:

>personally *think* that the idea of Early Jurassic dromaeosaurs (or 
>should I be saying Raptors[tm] in this case?) using predatory claws 
>to scramble up trees with broomsticks stuck to their butts, then

        No weirder than any other idea.  I don't want to know about that
butt thing, though...
 
>(yes yes, I do realize that it takes millions upon millions of of
>years of Raptors jumping out of trees after bugs for wings to
>evolve).

        And you suppose these protobirds were using their sicle claws o
killl bugs?!?!?  Really?!?!?

>and it still sounds just as...odd. yes yes, I'm aware of goats as 
>well.

        Shh... that's classified!  :)

        Wagner
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