Target discrimination by the echolocation of bats

Myotis lucifugus first learned to catch mealworms mechanically projected into the air in a laboratory flight room, and were then trained to distinguish mealworms from small metal or plastic disks (3.0 × 12.5 mm and 0.5 × 6.3 mm). These three targets were presented singly in a semi‐random sequence, traveling along very similar trajectories. The most skillful bats caught 98% of the mealworms while avoiding any contact with 85 to 90% of the two types of disks. Echoes of 100–20 kc pulses (similar to the bats' orientation sounds) were measured from all three targets in almost all possible angular orientations. There was great overlap in intensity both in the peak amplitudes and in each of the ten 8 kc bands from 100–20 kc. These bats thus seem capable of some qualitative discrimination based on the “fine structure” of echoes from small moving targets.