Surgical castration and the effect on aggression in rock hyrax (Procavia capensis)

Lincoln Park Zoo acquired five intact, male rock hyraxes (Procavia capensis) from three separate institutions to exhibit as a group. The animals were of varying ages at the time of acquisition. During quarantine, all five were surgically castrated via a midline laparotomy technique in an attempt to reduce expected aggression within the group. Recommendations for successful castration, based on these five procedures, include performing the procedure on sexually immature hyraxes or sexually inactive adults, the use of a second surgeon during the procedure, and the use of stainless steel surgical clips for ligation of vessels and spermatic cord. Although combinations of the castrated animals coexisted for longer periods than those documented for other nonrelated male groups, aggression was significant and resulted in the death of one individual. Ultimately, all animals were housed individually.