A cyst on a ferret's tail might be a chordoma. You can look at one here - http://www.afip.org/ferrets/chordoma.htmI [htm or html, not htmI] I recently read about this in the FHL. It's something that needs immediate attention per Dr. Bruce Williams: >Chordoma is a common musculoskeletal tumor which arises in the spine, >and most often in the tail. No, these tumors do not metastasize, and he >will not die of it. These tumors do eat into the bone of the veterbrae, >and this is painful; but the good news is that amputation of the tail is >curative. Let's get it removed as soon as possible. > >With kindest regards, >Bruce Williams, dVM" Hope this helps. Roary Albuquerque, NM [Posted in FML issue 4411]