[Passive hearing stability in the bottle-nosed dolphin Tursiops truncatus to low frequency noise spectrum deformation].

In behavioral experiments on bottle-nosed dolphins there was evaluated efficiency of identification of the low frequency noises that represent a certain rhythmical sequence of impulses, at destabilization of their spectra by method of frequency wobble. Results of the experiments have shown that disturbance of spectra structure at erosion of its discrete components does not lead to a decrease of efficiency of the noise identification, which indicates the greater significance of the time, rather than spectral mechanisms at processing of the complex acoustic signals by the dolphin auditory system.

[Recognition of classes of noise-like signals by dolphins Tursiops truncatus].

The ability of the auditory system to perceive and to classify the noise-like signals imitating natural sea noises has been studied in dolphins Tursiops truncatus. Results of the studies carried out in a sea bay at free movement of the animals have shown that dolphins are able to determine noise-like signals and to ascribe them to a certain class by using invariant characters, such as rhythmical sequence of impulses, regardless of the frequency-time scale of the signal presentation.