The effects of steady-state acoustic stimulation on resistance of fatigue, as shown by reduction of swimming time, was studied on three sublines of mice, one of which is genetically deaf. High frequency (500-10000 Hz) reduce swimming time from 25% to 50% in mice with normal hearing at a 60-80-dB threshold, but have no effect on deaf mice. Low frequencies and infrasounds (6-50 Hz) reduce swimming time in all mice similarly, even deaf animals, but the threshold is higher (160-115 dB). The use of genetically deaf animals therefore permits elimination of the auditory component; differentiation of the effects of air-borne from those of mechanical vibrations are thus possible.