[Noise resistance of the dolphin auditory analyzer as a function of the directional angle of the noise].

Masked tonal thresholds by noise in the bottlenose dolphin have been measured as a function of angle of noise direction. Sharp directional selectivity of hearing has been discovered resulting in an abrupt decrease of noise masking with the increase of the angle of noise coming. It has been shown that narrow directional characteristics of hearing is an angle 8 degrees plus or minus 2 degrees for the level of minus 3db. It is one of the main mechanisms supplying the echolocation system of the dolphin with the high level of resistance to noise.