Not to disagree too strongly with the keeper of the oracle, oh woman of diversity, da Wolfie, but (as a researcher) there IS a scientific means of testing the hearing in ferrets. AND, I do have in my possession several articles about the hearing sensitivity of the ferret. However, most of the research done in this area is because of the similarity between hearing and anatomical structure of the ferret and human ears. Unless you specifically went hunting for this info, you probably will not just happen onto it. If you are interested in references, please email me and I will send them. As a ferret mom, I have a lovely deaf gent, Sir Walter (of Raleigh, NC), who appears to communicate telepathically. Bob Church presented a wonderful talk at the Ferret Symposium 2002. He stated that ferrets speak to each other in sounds that are inaudible to humans. This makes me think that there must be some frequencies that can have adequate hearing sensitivity to function, without having adequate hearing sensitivity to respond to a variety of other sounds. Now, as an audiologist, I have contemplated testing the hearing of ferrets in my sound booth. I think that I can condition them to respond for a treat anytime I present a tone. However, I am not sure they would agree to the insert earphones and the headphones are too big ... renee :) & The Poop-in-the-Corner Gang [Posted in FML issue 3906]