Victoria, This is in reference to your friend's ferret Boo (7 yrs. old, with weakness in the hind legs). There are some things that can cause this including: 1)Insulinoma (pancreas tumors) can present this way. This disease can lead to weakness,salivation, glassy look in eyes. This is a serious disease that requires treatment. 2)Intervertebral Disk Disease (slipped disk)- this results in pressure on the spinal cord to the hind legs, weakness in the hind legs and stumbling or dragging the hind legs. 3)Lymphosarcoma-this can effect the spinal cord and cause weakness in the in legs. I do know a veterinarian in/near St Louis who treats ferrets. Dr. Wayne Boillat 314-537-3915 Good Luck. I trust you'll find Dr Boillat helpful. Dr Weiss 301-299-4142 [log in to unmask] [Posted in FML issue 1133]