Trish Freeman is visiting our lab at present, so we are trying to get
some insight into how bat's teeth work.  Apart from various obvious
models such as cutting up insects using instrumented scissors, there
arises Trish's observation that the cutting (Mode III) edges of the
upper and lower molars in the bat's jaw interact very much like pinking
shears, which have a zig-zag profile of the cutting edge.  When cutting
cloth, this profile is supposed to hold the cloth in position so that
several layers can be cut without them slipping sideways (try cutting
several layers of cloth, or paper, with straight scissors and see how
easy it is for the cut to go out of line).  It is then apparent that the
bat, since it chews while flying (which is more than Gerry Ford could
do, allegedly) needs to be sure that the food doesn't slip out of its
mouth.  The pinking action, plus the presence of large canines which
give the tooth row and end-stop, would seem to fulfil this requirement.

So, Q. 1 (for 10 points) has any work been done on the way pinking
shears work?

The above thoughts also led to the idea that the scales on lepidopteran
wings act very much like a graphitic lubricant and make it more
difficult to hang on to it (e.g. bird beak, bats, etc).  It seems to me
that this could explain why they are so easily removed.

And therefore Q. 2 (for 20 points) has anyone measured the dry
lubricating properties of scales on lepidopteran wings?

Thanks for your time
Julian
--
Julian FV Vincent                              [log in to unmask]
Professor of Biomimetics                        office 01225 386596
Centre for Biomimetics & Natural Technologies   mobile 07941 933901
Dept of Mechanical Engineering                  fax    01225 386928
The University
BATH  BA2  7AY

http://www.bath.ac.uk/Departments/Eng/biomimetics/

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