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Re: pterosaur flight & flocking behaviour



Stephan Pickering wrote:

> overlooked is the variety (inferred, I confess) of
> flight among pterosaurs.

Overlooked by whom?  

> However,
> "swarm" behaviour -- "flocking" -- among pterosaurs is
> one avenue of speculation.

There are several distinct types of flocking or swarm behavior among
birds and bats.  Since some pterosaurs have been found in close
association on the ground, it is not inconceivable that some may have
done so in the air, using any of several flocking techniques.  Proving
it might be a different thing.

> In the main, as Craig Reynolds notes,
> there are three steering behaviours in flocking: 1)
> separation: avoid crowding; 2) alignment: steer
> towards average heading of flockmates; 3) cohesion:
> steer towards the average position of flockmates.

There are at least two others.  Steer toward the individual with best
demonstrated lift and steer toward the individual that is making a fast
cross-country descent (toward a target).  Hyenas are known to watch for
the latter behavior and also steer toward the fast descender
(Pennycuick, if I remember correctly).

> With the plethora of excellent pterosaur specimens
> available, has Chris Bennett, e.g., thought of doing
> computer simulations of the biomechanics of flight
> among various pterosaur taxa?

Don't know about Chris, but I have.  Wasn't concerned with flocking
behavior though.

> Is there fossil evidence
> to indicate, e.g., their flight biomechanics was
> analogous to flapping dinosaurs, or to bats?

Yes.  All three are equally interesting for the things they do
differently, as well as the things they do similarly.

> Bats do not fly like dinosaurs.

In some respects, they do.  In others, they are different.  The same is
true of pterosaurs, and between different species of pterosaurs.  And
bats.  And birds.

> I believe pterosaurs were better fliers
> than some have contemplated.

There are a lot of folks out there, so this is almost certain to be a
true statement.  The converse is probably also true.  Some of the latest
pterosaurs seem to have been about as efficient as albatrosses, and some
of the same techniques for extracting energy from the atmosphere were
available to both, even though life styles would not necessarily be
expected to be similar.  At least some of the pterosaurs with heavier
wingloading appear to have operated as motor gliders, with sequences of
soaring alternated with about 1 to maybe 20 intermittent flaps.  Also,
I'm particularly taken with the technique wandering albatrosses use to
extract energy from the lee behind waves, and the possibility that
Quetzalcoatlus sometimes used the same technique with the lee behind
tree and shorelines.

Jim