Warren B. Ballard’s scientific contributions

We successfully immobilized 185 grizzly bears (Ursus arctos horribilis) with tiletamine hydrochloride (HCl) and zolazepam HCl during May-June 1986-87. One hundred eighty bears were captured in several areas in Alaska by darting from a helicopter; 5 were immobilized from traps or snares in Banff National Park in Alberta, Canada. Use of the recommended dose for immobilizing grizzly bears (7-9 mg/kg) resulted in a mean induction time of 4.1 ± 1.8 (SD) minutes and a safe handling period of 45-75 minutes. Tiletamine HCl/zolazepam HCl was an excellent drug for immobilizing grizzly bears because of rapid induction, timely and predictable recovery, wide safety margin, and few adverse side effects.