Abstract
China has various ecologically important sites that provide wonderful research opportunities. The biosonar behavior of Yangtze finless porpoises (Neophocaena phocaenoides asiaeorientalis) in the semi-natural reserve, Hubei, China has been extensively studied for the past five years by the Japan Fisheries Research Agency and Institute of Hydrobiology, Chinese Academy of Sciences. Careful scanning and acoustical autofocusing behavior in porpoises was firstly observed in free-ranging conditions. The biosonar model obtained in this study allowed us to recently develop a broadband high-resolution sonar system called the Dolphin Sonar Simulator. Frequent biosonar production by finless porpoises also allowed an effective passive acoustical survey to be conducted of the animal along the entire habitat of this species in 2006. Bilateral collaboration with cutting-edge acoustical technologies was proven to be highly productive for basic behavioral science, engineering applications, and the conservation of endangered species.