[Comparative evaluation of the response of rat-mothers to the natural pain squeaks of a ratling and to a tape recording of it].

Two kinds of stimuli were presented to the mother rat at random: the natural pain acoustic signal of its infant in response to electrical pain stimulation and the tape recording of the signal performed within the sound frequency region (up to 20 kHz). The mother rat was placed in a special long cage with two parts of different size. Her reaction was ethologically estimated. The natural pain signal proved to be more effective than its magnetic tape recording. The role of the spectrum ultrasound part of the pain acoustic signal is discussed.