Re: "Round-tailed ferret"--Sounds like a Chondroid Chordoma--and yes, it should be looked at by a Vet! My one personal experience with one was a few years ago, and required a tail amputation when the growth starting getting larger. If your Vet said it was "nothing", without doing any diagnostics, then I would get the opinion of a DIFFERENT Vet. Hope this helps-- [Posted in FML issue 4466]