Clutter resilience via auditory stream segregation in echolocating greater mouse-eared bats

Area of Science:

• Animal behavior
• Bioacoustics
• Sensory neuroscience

Background:

• Bats use echolocation for navigation and hunting in darkness.
• Segregating target echoes from clutter is crucial for bat echolocation.
• Spatial avoidance is one strategy, but how bats handle unavoidable clutter is unknown.

Purpose of the Study:

• To test if bats adjust echolocation call parameters (source level, call interval) to mitigate unavoidable clutter.
• To investigate if bats employ biosonar adjustments or rely on auditory processing for clutter rejection.

Main Methods:

• Five greater mouse-eared bats (Myotis myotis) were trained to land on a target.
• A phantom-echo setup simulated clutter by replaying bat calls with time delays.
• Target strength of simulated clutter was higher than the physical target.

Main Results:

• Bats successfully landed on the target despite simulated clutter.
• Bats did not decrease source levels or increase call intervals in clutter trials.
• Source level and call interval distributions were similar in clutter and control conditions.

Conclusions:

• The hypothesis that bats adjust biosonar parameters for clutter mitigation was rejected.
• Bats demonstrate resilience to clutter through short auditory integration times.
• Acute auditory stream segregation abilities are key to bats' success in cluttered environments.