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]