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Re: Dodos, Swifts and Quetzalcoatlus.



[no offense meant to the contents, sensitive stuff if one one wants to
read]

Jim Cunningham (jrccea@bellsouth.net) wrote:

<<For some of the larger pterosaurs, this would appear to be unlikely in
the extreme.  An animal that can walk around stablely (sp??) in
quadrupedal posture with its eyes 18 feet in the air doesn't have much
need to rear up and walk unstablely on its hind legs just so its eyes can
reach 19.5 feet into the air.>>

and Dave Peters (davidrpeters@earthlink.net) wrote:

<Except when its ready to hump something>

  I would not expect an animal that can raise its bulk at the shoulder
some foot in height just by extending the humerus ventrally to need to
raise it a further half a foot by standing on its hindlegs, unstably,
wobbly or whatever, to walk over and lay atop something, when it seems a
quadupedal posture can do this just as effectively. Most [male] quadrupeds
who become bipedal to "hump" are VERY ungainly when they do so (take the
most agile of these, gazelles -- giraffes aside) who have shorter
forelimbs than hind and immediately assume the quadrupedal posture after
coitus is completed; giraffes have longer fore than hindlimbs, but also
are promptly qudrupedal after mating, and force no habitual bipedalism to
be evolutionarily selective. Jim's point about the annoying 1.5 feet
difference would not seems to be much of a benefit to force a bipedal
stance in any situation, and so far, no mammal has become bipedal in order
to mate better, even human ancestors were faculatively bipedal prior to
our rather inverted mating postures (and aside from odd Tantric practices,
are seldom done standing). It would seem impractical to provide bipedalism
in pterosaurs so they can "hump" :) [this whole paragraph is
tongue-in-cheek, mind ;)].

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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