Bodson Anais, Miersch Lars, Mauck Bjoern, Dehnhardt Guido
General Zoology and Neurobiology, University of Bochum, ND 6/33, D-44780 Bochum, Germany.
J Acoust Soc Am. 2006 Sep;120(3):1550-7. doi: 10.1121/1.2221532.
The underwater sound localization acuity of a swimming harbor seal (Phoca vitulina) was measured in the horizontal plane at 13 different positions. The stimulus was either a double sound (two 6-kHz pure tones lasting 0.5 s separated by an interval of 0.2 s) or a single continuous sound of 1.2 s. Testing was conducted in a 10-m-diam underwater half circle arena with hidden loudspeakers installed at the exterior perimeter. The animal was trained to swim along the diameter of the half circle and to change its course towards the sound source as soon as the signal was given. The seal indicated the sound source by touching its assumed position at the board of the half circle. The deviation of the seals choice from the actual sound source was measured by means of video analysis. In trials with the double sound the seal localized the sound sources with a mean deviation of 2.8 degrees and in trials with the single sound with a mean deviation of 4.5 degrees. In a second experiment minimum audible angles of the stationary animal were found to be 9.8 degrees in front and 9.7 degrees in the back of the seal's head.
在13个不同位置的水平面上测量了一只正在游泳的港海豹（Phoca vitulina）的水下声音定位敏锐度。刺激源要么是双声（两个6千赫的纯音，持续0.5秒，间隔0.2秒），要么是持续1.2秒的单连续音。测试在一个直径10米的水下半圆竞技场中进行，隐藏的扬声器安装在外围。训练这只动物沿着半圆的直径游动，并在信号发出后立即朝着声源改变路线。海豹通过触碰半圆边缘处其假定的声源位置来指示声源。通过视频分析测量海豹选择的位置与实际声源之间的偏差。在双声试验中，海豹定位声源的平均偏差为2.8度，在单声试验中平均偏差为4.5度。在第二个实验中，发现静止动物的最小可听角度在海豹头部前方为9.8度，在头部后方为9.7度。
