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]