Adaptations to changes in the acoustic scene of the echolocating bat

echolocation;bat;acoustic interference;flight;echo flow;neural;behavior;eptesicus fuscus;navigation;Psychology

Warnecke, MichaelaMittal, Rajat ;

Johns Hopkins University

关键词: echolocation;    bat;    acoustic interference;    flight;    echo flow;    neural;    behavior;    eptesicus fuscus;    navigation;    Psychology;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/61116/WARNECKE-DISSERTATION-2018.pdf?sequence=1&isAllowed=n

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

Our natural environment is noisy and in order to navigate it successfully, we must filter out the important components so that we may guide our next steps. In analyzing our acoustic scene, one of the most common challenges is to segregate speech communication sounds from background noise; this process is not unique to humans. Echolocating bats emit high frequency biosonar signals and listen to echoes returning off objects in their environment. The sound wave they receive is a merging of echoes reflecting off target prey and other scattered objects, conspecific calls and echoes, and any naturally-occurring environmental noises. The bat is faced with the challenge of segregating this complex sound wave into the components of interest to adapt its flight and echolocation behavior in response to fast and dynamic environmental changes. In this thesis, we employ two approaches to investigate the mechanisms that may aid the bat in analyzing its acoustic scene. First, we test the bat’s adaptations to changes of controlled echo-acoustic flow patterns, similar to those it may encounter when flying along forest edges and among clutter. Our findings show that big brown bats adapt their flight paths in response to the intervals between echoes, and suggest that there is a limit to how close objects can be spaced, before the bat does not represent them as distinct any longer. Further, we consider how bats that use different echolocation signals may navigate similar environments, and provide evidence of species-specific flight and echolocation adaptations. Second, we research how temporal patterning of echolocation calls is affected during competitive foraging of paired bats in open and cluttered environments. Our findings show that ;;silent behavior”, the ceasing of emitting echolocation calls, which had previously been proposed as a mechanism to avoid acoustic interference, or to ;;eavesdrop” on another bat, may not be as common as has been reported.