The acoustic world of bat biosonar

Abstract

Bats and toothed whales (odontocetes) have both independently evolved sophisticated biosonar systems. This raises the question how similar the functional principles of these systems are. Could, for example, insights gained from bats be assumed to hold for odontocetes or vice versa? Could both systems be lumped together as a single source of inspiration for novel engineering approaches to sonar sensing? Similarities and differences between the biosonar systems of bats and odontocetes are likely to depend on the respective acoustic environments in which these systems have evolved as well as on the evolutionary starting points and capabilities for adaptations of these two very different phylogenetic groups. In this presentation, the focus will be on comparing the acoustic environments of bats and odontocetes. The acoustics of biosonar sensing can be organized into three different aspects: (i) the properties of the propagation medium, (ii) the geometry and material of the boundaries that limit the propagation channel (this includes targets of interest and clutter), and (iii) the time-frequency and spatial properties of the sources. In this presentation, these aspects will be reviewed for the in-air biosonar of bats. In the companion talk, the same will be done for the underwater biosonar of the odontocetes.