In this paper, in order to improve the entertainment dolphin robotpsilas ability to interact with people, a pair of microphones as the ears of a dolphin robot is used to estimate the peak sound directions from surrounding viewers. Dolphin robots should turn towards people who want to interact with them, while swimming autonomously. A pair of left and right microphones is located to form the binaural ears of a dolphin robot. Since the magnitudes of the measured microphone signals decrease as the difference between directions of the microphone and sounds increases, the magnitudes of the left and right signals of microphones are compared to find the sound direction relative to the robotpsilas body line. The same rule applies to the second pair of microphones to determine the sound direction relative to the front.