Perception of Distance in Animal Echo-Location

Abstract

IN a recent article¹ Nordmark fails to explain two features of the bat's ultrasonic transmissions; one is the frequency sweep used by most species of bat employing echo-location as a means of orientation, and the other is the apparent difference between Vespertilionidae and Rhinolophidae which in fact has been shown to be a similarity². As with all hypotheses related to the behaviour of animals none can be proved beyond doubt, nor can we expect any to be complete; we may, however, assume reasonable efficiency in the use of the information contained in echoes received by the bat as it relies on such information for its very livelihood.