Michaela Warnecke

10:30 am on Friday, September 14, 2018
12:00 pm on Friday, September 14, 2018
44 Cummington Mall, room 401 - Please note, this is not our usual room
Behavioral adaptations to changes in the acoustic scene of the echolocating bat Our natural environment is noisy and in order to navigate it successfully, we must filter out the important components that may guide our next steps. For humans, a common challenge in analyzing the acoustic scene is the segregation of 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 acoustic input they receive is a complex sound containing echoes reflecting off target prey and other scattered objects, conspecific calls and echoes, and any naturally-occurring environmental noises. The bat is thus 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 talk, I will discuss two approaches to investigate the mechanisms that may aid the bat in analyzing its acoustic scene. First, I will discuss how bats adapt their behavior in open spaces and cluttered environments. More specifically, I will outline how temporal patterning of echolocation calls is affected during competitive foraging of paired bats. The results of these experiments 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 previously reported. Second, I will outline 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. The findings of these studies 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. Binaural Hearing and Speech Lab, University of Wisconsin-Madison.