Okay, I heard back from a vet that, YES, things like the thickness and
sensitivity of the esophagus in various species DO differ according to
dietary adaptations.  For example, one of the thickest and least
sensitive is that of the duck.  Ducks swallow fish whole.  So perhaps
dietary eating habits like food bolting and regurgitation, and repeated
injury do play a role in MegaE propensity among ferrets.  (See discussion
on FHL for more info such as neuro stuff.  In other species there are a
few examples of genetic propensity, many of injury cause, and many of
neuro cause.)
 
-- Sukie (not a vet)
Ferret Health List co-moderator
http://www.smartgroups.com/groups/ferrethealth
FHL Archives fan
http://ferrethealth.org/archive/
replacing
http://fhl.sonic-weasel.org
International Ferret Congress advisor
http://www.ferretcongress.org
[Posted in FML issue 5037]