The Conibear 330 failed to render irreversibly unconscious in < or = 3 min one lynx (Felis lynx) struck in the shoulders and two of eight lynx struck in the neck region, in simulated natural environments. A Conibear 330 with two clamping bars rendered unconscious in < or = 3 min eight lynx struck in the neck and one struck in the shoulders. The mean (+/- SE) times to loss of consciousness and heartbeat were 67.2 (+/- 4.0) sec and 196.0 (+/- 10.4) sec, respectively. This modified Conibear 330 can be expected to render > or = 70% of captured lynx irreversibly unconscious in < or = 3 min (P < 0.05).