. Echoes of bats and men. Sound-waves; Echolocation (Physiology); Orientation. ECHOES OF BATS AND MEN fish below the surface. In any event, the fish-catching species make much of their living in this way, and during their recent evolutionary history a relatively small ana- tomical adaptation has resulted in the specialized fish- gafiSng claws. When I have watched these bats in Panama, I have seen no sign that the fish were moving or disturbing the surface of the water in any way. Often it was glassy calm, and the bat flew for hundreds of feet a few inches above the surface, quickly lowering th
. Echoes of bats and men. Sound-waves; Echolocation (Physiology); Orientation. ECHOES OF BATS AND MEN fish below the surface. In any event, the fish-catching species make much of their living in this way, and during their recent evolutionary history a relatively small ana- tomical adaptation has resulted in the specialized fish- gafiSng claws. When I have watched these bats in Panama, I have seen no sign that the fish were moving or disturbing the surface of the water in any way. Often it was glassy calm, and the bat flew for hundreds of feet a few inches above the surface, quickly lowering the hind feet into the water for a short distance and then raising them while continuing its low-altitude searching flight. How do these bats know where fish are to be captured? They are evi-. Fig. 13. Motion pictures of fishing bats actually gaf- fing minnows provided the model for this drawing. Prentice Bloedel took the photographs. dently selective in their fishing, for they fly long distances just above the water and only rarely dip their claws be- neath the surface. Since the fishing occurs on dark and misty nights, it is most unlikely that the fish could be seen and still less probable that they emit any sound audible to the bat flying in the air above the surface. Could it be that the fish-catching bats detect echoes from fish beneath the surface? At first glance this may seem only a slight modification of the process by which closely related bats catch insects in the air. But the physical dis- continuity between air and water makes the transmission 96. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Griffin, Donald R. (Donald Redfield), 1915-. Garden City, N. Y. : Anchor Books
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Keywords: ., bookcentury1900, bookcollectionbiodivers, booksubjectorientation
