These can occur anywhere along the spine, but in ferrets, they most commonly occur at the tip of the tail. Chordomas are considered potentially malignant, however, metastasis has not been seen in these neoplasms arising in the tail. These should be removed for a number of reasons. Tumors of the bone can be painful, there's increased risk of injury to the tail simply because of the large knot on the end and it would be terrible if your ferret was the one case where it was malignant and metastasis occurred. Amputation of the necessary segments of the tail is curative and the ferret will be happier with a tail that is a bit shorter but without the tumor. Ref: http://miamiferret.org/faq.htm#chordoma We had a 4-year-old female ferret with a chordoma at the end of her tail. It was just a small ball, barely visible, but you could feel it. It was slow growing, and you could tell it was painful as she would always keep her tail elevated. Since it was so small when it was removed, she only needed about an inch of tail amputated. Surgery was early in the morning, and by 5pm she was ready to come home. You could tell it was a relief to her to have it gone. She was a brat that night, climbing all over - you couldn't tell, other than the shaved portion of tail with stitches at the end, that she just had surgery that day. She had pain management for a couple days, and had a quick recovery. Her tail fully furred again with the next shed. Hope this helps. [Posted in FML 7315]