Inaudible Animal Communication

◆ Did you know that certain animals communicate with one another with sounds that man cannot hear? The book The Mating Instinct by L. J. and M. J. Milne explains why this is so: “Man’s own hearing extends over a range of pitches from 16 to about 15,000 cycles per second​—some ten octaves—​a spread wherein his own and his mate’s voice may span four octaves if he is a basso profundo and she is high soprano. But sound continues well beyond 15,000 cycles. . . . Man is growing to realize that the usual stillness of the forest at night conceals​—through his own limitations in hearing—​a vast array of squeaky whispers that permit communication between smaller animals.”