Scanning behavior in echolocating common pipistrelle bats (Pipistrellus pipistrellus)

Area of Science:

• Bioacoustics
• Animal Behavior
• Sensory Ecology

Background:

• Echolocating bats create a spatial understanding through sequential pulse-echo analysis.
• Mammalian vision relies on sequential foveal fixations and gaze saccades for environmental perception.

Purpose of the Study:

• To investigate and characterize the three-dimensional sonar beam scanning behavior in bats.
• To compare bat echolocation scanning patterns with visual scanning strategies.

Main Methods:

• Utilized a 16-microphone array to determine sonar beam direction and characterize scanning behavior in Pipistrellus pipistrellus.
• Analyzed flight sequences and echolocation calls to assess bat positions, source levels, and beam aiming.
• Employed signal amplitude variations to indicate scanning behavior in open environments.

Main Results:

• Bats display varied scanning patterns, including back-and-forth movements and irregular sequences, depending on the echolocation task.
• Scanning angles were wide and task-dependent, often exceeding the measurable range of the array.
• Approaching targets resulted in smaller, step-wise scanning movements.

Conclusions:

• Echolocating bats employ a "saccade and fixate" strategy analogous to visual scanning.
• Scanning movements enable bats to effectively locate and explore targets within a broad search cone.
• Bat scanning behavior is adaptable and task-specific, optimizing environmental exploration.