Hi Eric developed a bump on the tail. It was red in colour with dark spots and spherical in shape. Initially it grew slowly but accelerated after a while but showed no signs of bothering Eric. We suspected it was malignant disease but did not want to biopsy and risk disturbing it. After removal it turned out to be a type of chordoma, a tumor that grows at the extremes of the axial skeleton (top or bottom of spine). They can be very aggressive and spread easily. We were lucky as erics lump was at the tip of his tail and easily accessed but his entire tail was removed as a precaution. For all that this made him look a little odd neither he nor the other weasels ever seemed to notice. He soon made a full recovery. Please see a vet about this just to be safe. If you want any more information please reply to [log in to unmask] as I will not be on my work e-mail address for the next few days. Wayne. Wayne Gardner Clinical Scientist Dept. of Medical Physics Bradford Teaching Hospitals NHS Foundation Trust Bradford Royal Infirmary BD9 6RJ Tel. 01274 364144 Fax. 01274 364134 [log in to unmask] [log in to unmask] [Posted in FML issue 4824]