Marine mammal echolocation provides a model of forthcoming bio-oriented sonar

Cetacean´s sonar is an appropriate model of underwater acoustical sensing technology. Sonar behavior of three free-ranging finless porpoises in an oxbow of the Yangtze River was observed by microdata logger systems attached on the animals. Newly developed acoustic data logger could record porpoise´s sonar pulse events 1000 times every second with the amplitude information. Close correlation between sonar effort and behavioral context could be observed. Frequent use of sonar with various inter-pulse intervals was recorded during quick body movements characterized by spiky change of heaving acceleration. The inter-pulse intervals were precisely controlled to adjust the distance to a remote target, which was similar to the terminal phase in bat´s sonar behavior