Hearing in the Animal World

You have a right to be impressed with the wonder of human hearing. But what about that of other creatures? Well, people can see the external ears of dogs, cats, horses and monkeys, and they know that such animals respond to sounds. Also, though birds lack external ears, most persons are well aware that these creatures can hear. As a matter of fact, a bird’s auditory range is about the same as man’s. What about snakes? Can they hear?

Some naturalists contend that snakes cannot hear. Actually, however, recent findings show that these animals have an auditory mechanism and can hear fairly well. For instance, researchers Peter H. Hartline and Howard W. Campbell found that not only substrate vibrations but also airborne sounds evoked electrical responses in species of three snake families. Concerning a boa constrictor, they wrote: “If a brain response is accepted as indicative of hearing, these snakes can hear airborne sound.”​—Science, March 14, 1969, Vol. 163, No. 3872, page 1222.

The Bible implies that the cobra can “listen to the voice of charmers.” (Ps. 58:4, 5) In this regard, the New York Times of January 10, 1954, stated: “Dr. David I. Macht, research pharmacologist of the Mount Sinai Hospital in Baltimore, is one of the world’s leading authorities on cobra snake venom. . . . Dr. Macht reported that in working with cobras and cobra venom he became acquainted with a number of Hindu physicians, well educated, and from different parts of India. All agreed that cobras respond to some musical tones, from musical pipes or fifes. Some forms of music excite the animals more than other forms, the physicians reported. Indian children, playing in the dark in the countryside, are even warned not to sing lest their sounds attract cobras, he said. Dr. Macht commented that Shakespeare, who repeatedly referred to serpents as deaf . . . merely repeated a common misunderstanding. On the other hand, Dr. Macht said, the psalmist was right who implied conversely, in Psalm 58, Verse 5, that serpents can hear: . . . Contrary to the claims of some naturalists, Dr. Macht said, snakes are ‘charmed’ by sounds, not by movements of the charmer. Revise the textbooks, the physicians recommended.”

Some creatures employ the sense of hearing in quite an extraordinary way. They are equipped for echolocation. These animals emit high-frequency sounds and are guided, by listening and responding to rapidly returning echoes as the sounds are reflected by objects. For instance, bottle-nosed dolphins use this method to avoid underwater obstacles.

Among echolocators is a well-known flying mammal​—the bat. If you were to release a bat in a completely dark room, it could-fly about without hitting the walls or other objects. This is because the animals emit sound pulses of high frequency; as the sounds strike obstacles, they listen for the echoes. Why, they sometimes send out over 200 pulses a second! By interpreting the messages resulting from these echoes, the creature-charts a safe course.

The bat also uses its astounding guidance system to locate the insects on which it dines. But just how it tells the difference between echoes reflected by obstacles and those returning from potential meals remains a mystery to man. For that matter, certain bats catch their prey right on the obstacle, a leaf.

Another remarkable factor is that the bat does not hear the sounds it emits. Every time one is sent out, ear-muscle contractions ‘turn off the sound’ so that only the echo is heard. Furthermore, each bat may possess and follow its own pattern of sound because there is not mass confusion when hundreds of these creatures flock together.

What a system of sound emission and hearing the Creator has given the bat! It has been said: “Scientists estimate that, ounce for ounce and watt for watt, the bat’s sonar is a billion times more sensitive and efficient than any radar or sonar device contrived by man.”​—James Poling, in Marvels & Mysteries of Our Animal World.