Effective biosonar echo-to-clutter rejection ratio in a complex dynamic scene.

Area of Science:

• Behavioral Ecology
• Sensory Neuroscience
• Bioacoustics

Background:

• Bats utilize biosonar for navigation and foraging in complex environments.
• Understanding how bats process auditory information in cluttered spaces is crucial for deciphering sensory guidance mechanisms.

Purpose of the Study:

• To investigate how big brown bats (Eptesicus fuscus) use biosonar for guidance in a dynamic, complex environment.
• To determine if bats can detect and react to a weakly reflective obstacle within a cluttered soundscape.

Main Methods:

• Bats were trained to fly through a Y-shaped maze with reflective chains.
• A weakly reflective net barrier was randomly placed in one corridor, with flight paths and echolocation calls recorded using a microphone array.
• The two-choice Y-shaped paradigm was employed to control for spatial bias and memory.

Main Results:

• Bats successfully navigated the maze, adjusting their flight paths and echolocation beam aim.
• Acoustic and kinematic changes occurred approximately 1 meter before the barrier, indicating detection.
• Bats perceived the net's echoes despite them being significantly weaker (18-35 dB) than surrounding echoes.

Conclusions:

• Big brown bats can effectively use biosonar to detect and avoid obstacles in complex, cluttered environments.
• The bats demonstrated adaptive behavioral and acoustic adjustments in response to perceived threats, highlighting the sophistication of their biosonar system.