Drawing of the external ear of Eptesicus fuscus, including the pinna and the tragus (drawn by Kweelen Lee).
Schematic of setup for video and sound recordings of tethered prey capture by echolocating bats. Two high-speed IR cameras (Kodak MotionCorder Analyzer, 240 frames per second) were mounted in the room to permit 3D reconstruction of the bat’s flight path. Video recordings were synchronized with audio recordings taken with two ultrasonic microphones delivering signals to an IOTech Wavebook.
Measurements of adaptive motor behavior. (a) The elevation offset between the bat and the prey; (b) the velocity of the bat from the side view; and (c) the bearing from the side view.
Prey capture performance. (a) Prey capture performance under different conditions over repeated test days. The open circle summarizes direct target hits, the closed circle shows target contacts, and the closed triangle shows far misses. The axis represents the conditions (B as baseline, C as control, T as tragus-deflection, and R as recovery) and the number refers to test days 1 to 4. (b) Prey capture performance under different conditions. The letters above the histograms represent the rank of the performance. The same letter means no significant difference.
The range of capture measurement in E. fuscus. The black dot on the bat’s body is the center of the bat.
Sonar buzz duration across the three different conditions, baseline, tragus-deflection, and recovery. The letter in the histogram represents the rank of the buzz length.
The adjustment of flight path in different planes in the tragus-deflection condition. (a) Distance difference and (b) bearing difference in the horizontal (closed circle) and vertical (open diamond) planes. The difference is computed from the difference between mean values in baseline and tragus-deflection conditions in every time segment.
The bat’s adaptive motor behavior. (a) The elevation offset between the bat and the prey; (b) the velocity of the bat from the side view; and (c) the bearing from the side view in direct hit trials across the three conditions: baseline (asterisk), tragus-deflection (open triangle), and recovery (dot). The bat’s adaptive motor behavior: (d) the elevation offset between the bat and the prey; (e) the velocity of the bat from the side view; and (f) the bearing from the side view, in the three conditions, baseline condition direct target hit (B-DH) trials (asterisk), the first day tragus condition direct target hit (1st T-DH) trials (closed triangle), and the first day condition target contact (1st T-C) trials (open circle). Error bars represent the standard error of the mean.
The interaction distance under three different tragus conditions.
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