Avoidance of Obstacles by Bats

Abstract

I HAVE read with great interest Mr. Pike's article on bats¹ and Squadron Leader A. K. McIntyre's letter² commenting on it. As the latter correctly states, it was Galambos and Griffin who were largely instrumental in proving that bats employ a supersonic form of acoustic 'radiolocation' when flying at night. They were not, however, the originators of this hypothesis, as they themselves state in their papers. This hypothesis was advanced by me as the result of a number of experiments performed in a set of rooms in King's College, Cambridge, the windows of which looked out on to the Cam. During the summer months, bats flew into these rooms in large numbers in the late evening and would remain there until dawn, flying round and round at will. They were unwitting collaborators in my experiments and continued to visit me without fear until the end of the long vacation. As a result of these visits I wrote an article in which I advanced the hypothesis that bats detect and avoid obstacles by hearing reflexions of high-pitched vocal sounds emitted during flight.³