Surgical sterilization of free-ranging wolves

The objective of the study was to determine whether surgical sterilization of both males and females in wolf pairs alters basic wolf social and territ orial behaviors. Wolves were located from the air by snow-tracking methods and were tranquilizer-darted from a helicopter. Surgeries were performed ei ther in a tent at the capture site or in a heated building in a nearby vill age. Six vasectomies and seven uterine horn ligations were performed in Jan uary and February of 1996 and 1997. Two females died: one likely related to the capture procedure, the other of a peritonitis unrelated to the surgery . One wolf had a litter. None of the wolves have shown changes in behaviora l patterns. Surgical sterilization can be effective, but other, less invasi ve, fertility control techniques should be investigated.