 The tranquilizer drug causes the target to become faint and suddenly unconscious within 45 minutes .Because of the power of the drugs, the handlers then have to move quickly to secure the animal for transport, monitor its vital signs, protect its eyes and ears, and then inject antidotes when needed.Many large animals are acutely sensitive to stress and can easily die without careful treatment; in order to counter stress in targeted animals, the gun is quiet, and there is usually a valve on the gun to control the dart velocity by varying the amount of gas pressure used to propel it.