Effect of echoflow in the echolocating bat

Michaela Warnecke

Being interested in acoustical scene analysis and clutter rejection/target detection mechanisms, I am currently focusing on how the bat perceives and processes the continuously changing flow of acoustic information during flight, and the approaches it uses to distinguish a target prey from structurally similar clutter objects during flight. In this experiment, I am flying echolocating big brown bats through tunnels of wooden rods to present them with a situation of high clutter. The tunnel sides can have different configurations (for example densely cluttered on one side and sparsely cluttered on the other side). I hypothesize that bats steer their echolocation beam toward the less acousticallycluttered sides of the tunnel and adjust their flight behavior so as to avoid dense clutter. I further hypothesize that bats can navigate through such densely cluttered environments easily, as has been shown in previous research (Simmons et al. 2001, Moss and Surlykke 2010). When introducing a target prey, I hypothesize that the bat can successfully capture the prey and abandons possible “clutter avoidance steering strategies” to lock its beam onto the target and ignore incoming acoustic clutter.

These data are currently being processes and analyzed.

Example of the acoustic flow of echo objects during bat flight. Right panel show the waveform and spectrogram of a bat call (call 1) and the echoes returning to the bat from subsequent objects in the bat’s path.


Warnecke M & Simmons JA. Target discrimination and clutter detection use the same mechanism in bat sonar (in review).

Simmons AM, Horn K, Warnecke M & Simmons JA. Big brown bats (Eptesicus fuscus) do not experience hearing threshold shifts after exposure to intense broadband noise (submitted).

Warnecke M, Chiu C, Engelberg J, & Moss CF (2015). Active Listening in a Bat Cocktail Party: Adaptive Echolocation and Flight Behaviors of Big Brown Bats, Eptesicus fuscus, Foraging in a Cluttered Acoustic Environment. Brain, behavior and evolution, 86(1), 6-16.

Warnecke M, Bates ME, Flores V & Simmons JA (2014). Spatial release from simultaneous echo masking in bat sonar. The Journal of the Acoustical Society of America, 135 (5), 3077-3085.

Gaudette JE, Kloepper LN, Warnecke M & Simmons JA (2014). High resolution acoustic measurement system and beam pattern reconstruction method for bat echolocation emissions. The Journal of the Acoustical Society of America, 135 (1), 513-520.

Simmons AM, Warnecke M, Vu TT & Smith ATS (2014). Flow sensing in developing Xenopus laevis is disrupted by visual cues and ototoxin exposure. Journal of Comparative Physiology A, 1-19.


Simmons JA, Warnecke M & Gaudette, JE Biosonar transformations for target shape, clutter perception and Doppler shift ambiguity (in prep).

Warnecke M, Lee WJ & Moss CF. Acoustic echoflow in the echolocating bat (in prep).

Copyright@2015 Batlab, Johns Hopkins University
Questions and comments to wxian1@jhu.edu

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