Re: poling dangers

[David Peters <davidrpeters@earthlink.net>]

M. Habib wrote:

Well, I can see 'scouting', but Qn would not take off like a duck. In
fact, it took off "in reverse order" compared to a duck, in the sense
that the forelimbs leave last, rather than the hindlimbs leaving the
ground last (which allows ducks to run over the water while flapping).
If the water was relatively deep (which is what seemed to be implied),
such that the animal was poling on the forelimbs only, I cannot see how
it would take off. In shallow water it is not an issue; but in deep
water the forelimbs simply could not move through the fluid fast enough
to initiate a proper launch, as best I can make out. In addition, if the
animal is floating to any significant degree, it will have an awfully
hard time pre-loading the forelimbs for launch (imagine trying to leap
into the air without being able to bend your knees much)


>>>  I think you are having issues with the sticky problem of aquaeous
drag. If I'm reading your right, in your vision of the situation, I
sense a need to elevate the wings quickly, which would be difficult
under deep water during poling. Granted. Also, let's not forget that the
beak and neck might also be underwater during extreme poling. So the
problem you envision is real.

Three scenarios come to mind: 1) flying out from the spot. 2) poling and
kicking to the opposite end of the pond until it shallows. 3) Flapping
without flying to create such a splashy commotion that the bad guy heads
the other way.  3) Praying for deliverance. Sounds like you're
interested in No. 1.

1) As the head rises above the surface, the eyes, set far back on the
skull, break water, sense danger then things start moving. First,
everything flexes in panic. Flexion of the humerus brings the already
folded wing forward to the surface in a configuration the pterosaur
might also use to rest on  dry ground. The once relaxed femora splayed
at the surface, immediately flex (adduct), forcing the hips up and the
shoulders down. So far, not good ? but wait... Taking advantage of the
imminent bounce back, the neck rapidly elevates which helps rotate the
anterior torso momentarily and elevate the shoulders. At the same time
the thighs abduct creating a low pressure situation between the knees,
which sucks the posterior torso down, which elevates the shoulders in
this bizarre version of see-saw. This is how I see Q. raising the
shoulders above the surface. Momentarily freed from the water, the wings
snap laterally and start flapping, but only employing the top half of
the beat cycle in order to avoid reentering the water.

Once airborne, danger over.

Does this work for you? It's all speculation on my part. Hadn't thought
of this until painted into a corner. Could be all wrong.

David Peters
St. Louis