A Natural History of the Senses
Suppose it is a calm day, absolutely still, not a twig or leaf stirring. To me it will seem quiet as a tomb though hedgerows are full of noisy but invisible birds. Then comes a breath of air, enough to unsettle a leaf; I will see and hear that movement like an exclamation. The illusory soundlessness has been interrupted. I see, as if I heard, a visionary noise of wind in a disturbance of foliage.… I have sometimes to make a deliberate effort to remember I am not ‘hearing’ anything, because there is nothing to hear. Such non-sounds include the flight and movement of birds, even fish swimming in clear water or the tank of an aquarium. I take it that the flight of most birds, at least at a distance, must be silent.… Yet it appears audible, each species creating a different “eye-music” from the nonchalant melancholy of seagulls to the staccato of flitting tits …
West’s Words for a Deaf Daughter frequently appears in college syllabuses, but not, as one might imagine, only in courses for or about the deaf. Lavishly written, with much wit and phenomenological devotion, it also appeals to students of philosophy and literature as a jubilant hymn to language and life. Told in the second person throughout, it addresses and at times impersonates West’s deaf daughter Mandy. And, unlike many memoirs about handicapped children, it isn’t at all maudlin, but rompy, poetic, and concerned with the struggle we all wage to know ourselves and to make ourselves known. These books allow one to eavesdrop on the inner life of the deaf, a special privilege, since many people assume the deaf, especially if they don’t read or write, think differently, dwelling in a no-man’s-land between concept and word. But, as the literature of the deaf makes clear, ideas and emotions find their way through with surprising ingenuity, whether in English, Ameslan, or some other language, from silence to the inner world where words can be “heard.”
ANIMALS
An ancient Chinese proverb says: “A bird does not sing because it has an answer—it sings because it has a song.” Few animal sounds are as beautiful as bird song. Once you’ve heard a whippoorwill throwing the boomerang of its voice across the summer marshes, you listen with a new sense of privilege. Baby birds aren’t born knowing their song; they learn the song of their parents. If you raised some birds away from their parents and whistled a different song—the opening notes of Beethoven’s Ninth, say—then they would learn your song, and neighbors might well call them “the Beethoven birds.” Until they get the knack of making real songs, baby birds often babble and chatter and make a lot of noise that doesn’t seem to mean anything. Like human babies, they are discovering the shock of being able to make sounds at all; eventually they learn to control the sounds, and they practice. A voice is an elaborate instrument, which one can use without knowing much about it. But to make sense with it, you really need to know its limits and capabilities. Hence the babblings. Birds speak dialects, as people do. A New Hampshire crow that hasn’t traveled won’t respond to the call of a Texas crow, but crows from different regions get to understand each other just as fiddlers from different states do when they meet at a convention in the Ozarks.
Some animals hear in much higher or lower ranges than we do, and with a delicacy and finesse that’s astonishing. A dog can tell the difference between the sound of its master’s footsteps and those of other family members or visitors. My family once had a dog that could tell the sound of my mother’s car engine from any other traffic going by the house. In department stores all across America one can now buy a pair of what look like miniature foghorns, which attach to each side of a car. When the car goes about 35 mph, the wind rushing through the horns makes a high whistle that alerts deer, dogs, or other animals to get out of the way. It’s too high to annoy a human ear, but to a dog napping in the road it is like an air-raid siren. Deer are nearly silent, but they hear well. An experimenter in New Zealand was recently able to cause female red deer to go into heat by playing the sound of a male red deer’s mating roar. Fish don’t have outer ears, but they hear vibrations through the water as we hear sounds traveling through air. Some animals can move their ears like small radar dishes, without moving their heads. I’ve seen deer, cats, and horses run through arpeggios of ear twitching. Thanks to a clever arrangement of their ears—one slightly higher than the other—nocturnal owls can pinpoint a sound to within one degree, and the edges of their feathers are softly fringed to muffle the sound of their approach when they are hunting. It might be more convenient to have just one centrally located ear, but having two makes it easier to locate a sound, just as having two eyes provides depth perception. African elephants have big floppy ears that mainly pick up sounds from below, and they produce a low-frequency infrasound too low for us to hear, with which they communicate.* Insects often have ears on unlikely parts of their bodies, such as on their legs or under their wings.
I once knew an aging cat who, when she went into heat, kept meow-screaming “Now! Now! Now!” over and over like a berserk harmonica player as she staggered around the apartment, occasionally stopping to thrust her rump high in that feline invitation to mating known as lordosis. Few sounds are as lovely as those made by the tree frogs in Bermuda, Puerto Rico, and other sunny isles. Often not more than an inch long, such frogs sweetly call through the night like tuneful thumb harps. It’s thought that the coqui frogs of Puerto Rico locate sounds by using their lungs. Sound waves hit the sides of the frog’s body, and travel to the eardrum on a pathway through the lungs. In these days of superspecialization, we assume that the body specializes, too, evolving each part for one purpose. But as it turns out, some parts have various chores. Not only frogs, but some snakes and lizards as well, hear through their lungs; in porpoises and dolphins, sound is believed to travel through an oil-filled lower jaw. Not all animals use sound just for hearing. Sperm whales, bottlenose dolphins, and others may be using sound as a weapon. It is thought that they stun their prey with loud “bangs,” the blasts from which can even cause a small fish like an anchovy to hemorrhage internally.
Tonight the crickets are loud and furious, rubbing their wings into strident song. They seem to be singing in unison, but that’s just an accidental felicity. I’m not hearing them talk to one another at all, since crickets communicate in the ultrasonic range, too high for human ears. What I’m hearing is accidental and to them irrelevant sounds made by their scraping wings. If I were to record the chirps and play them back for the crickets, they wouldn’t answer. Animals seem to have their own lanes of sound, ones in which they communicate and to which their ears are most sensitive. If they didn’t, they’d have to shriek all the time to make themselves heard above the din of other creatures.
There are auditory niches. Nature allows an animal a little decorum and privacy when it comes to its own species.* Otherwise, a warning to its brethren would also signal a predator. Of course, this doesn’t always work as it should. One Central American bat, which has a special taste for the frog Physalaemus, stalks its prey by sound. It listens for the male frog’s mating call, knowing that the louder the song is, the plumper and juicier the frog will be. This puts the frog in an appalling predicament. Full of sexual longing in the steamy tropical night, it must sing loudly to attract a mate—but if it does, it may also attract a hungry bat. And yet a poor song attracts neither.
One day in December I went with bat expert Merlin D. Tuttle to Bracken Cave in Texas, a nursery cave where millions of mother and baby bats live. Just before sunset, we sat down in the natural amphitheater of stone outside the cave and waited for the thrilling spectacle we knew was ahead of us. As a ruddy sunset began, a few bats flew out of the cave, circled to gain altitude, and flew off into the night to feed; then a few more came, and dozens after that, and hundreds after that, until suddenly the sky was thick with them. Merlin and I could feel the strong breeze they made as they identified us by echolocation and flew close to our heads without hitting us. Then Merlin swung an arm up fast and grabbed one out of the air, holding it carefully so we could look at its adaptations for echolocation, obvious even in the skin on its face: little folds and flaps that work like radar
dishes.
Bats whistle or call to their prey with a steady stream of high-frequency clicks. For most of us, their vocal Braille is too high to hear, since bats click at an average of 50,000 cycles per second. In our youth, we could hear only sounds of up to 20,000. Bats click at intervals of ten or twenty times a second, and the “bat-detector” naturalists use translates the ultrasonic noises into warbles and clicks audible to human ears. Like winged megaphones, bats broadcast their voices, then listen for the sounds to bounce back at them. As they close in on their prey, echoes start coming faster or louder and, judging the time between the echoes, a bat knows how close its prey is. The solid echoes a bat hears from a brick wall or the ground sound different from the fluid echoes of a flower or leaf. A bat can build a complete echo picture of its world, a canvas on which all the objects and animals reveal themselves in detail, down to their texture, motion, distance, and size. If you stand in a quiet yard filled with bats, the bats will be shouting very loudly; you just won’t hear them. In The Scale of Nature, biologist John Tyler Bonner offers this way of putting echolocation into human terms:
I can remember going through the San Juan Islands in Puget Sound in a fog. The channel between the islands is very narrow, yet it was impossible to see either shore. The ferryboat pilot first politely told all the mothers to ask their children to stop their ears. Then he blasted his horn while he leaned out the pilothouse on one side, and repeated the operation as he leaned out the other side. By judging the time it took for the echo to return, he could gauge his distance from the shore. He seemed far more composed about the process than I.
Echolocation is just one of many animal sounds beyond our hearing. Praying mantises use ultrasonics; elephants and crocodilians use infrasonics. Few animal displays are as thrilling to watch as the “water dance” of a male alligator. Stretching its enormous head out of the water, it puffs up its throat, tenses hard like a body builder, and then a rolling thunder-buster bellow splits the air, and the water sizzles all around its body, raining upward like frying diamonds. We see the water dance, but other alligators hear its infrasonic signal, made only by the males, perhaps as a courtship display or perhaps also as a full-body raspberry directed at other males. Although female alligators bellow, too, and even slap their heads on the water from time to time, they don’t do a water dance. But they do read its message like seasoned code-breakers. And occasionally a male, hot and bothered and truly inspired, does a cluster of water dances—as many as eight or nine—in a long ballet of dance, song, and yearning.
We also don’t hear most underwater sounds, and that leads us to assume that the vast oceans are silent, which couldn’t be farther from the truth. Leonardo da Vinci once suggested dipping an oar into the water and listening, with one’s ear against its handle. Fishermen in West Africa and also in the South Seas discovered the same trick. Using the oar as a kind of listening straw, you can hear the sounds of the underwater world. Some fish are a noisy lot. Sea robins, drum-fishes and many others make sounds with their swim bladders; croakers grunt loud enough to keep China Sea fishermen awake at night; Hawaiian triggerfish grind their teeth loudly; the male toadfish growls; bottlenose dolphins click and squeak like badly oiled office chairs; bowhead whales purr and twirp; humpback whales put on a songfest. The ocean looks mute, but is alive with sounds from animals, breaking waves, tidal scouring, ship traffic, and nomadic storms, locked within the atmosphere of water as our sounds are within the atmosphere of air.
How empty the world would be without animal sounds. The blackbirds quibbling like druids. Horses galloping on a soft track. The crows, which sound as if they’re choking in the trees. The burbling chickadees hanging upside down from the branches. The elk’s bugling, like the sound of distant war games. The metallic ping of nighthawks. The kindergarten band of crickets (from the Old French criquet, “to creak”). The electric whine of hungry female mosquitoes. The Morse code of the red-headed woodpecker.
QUICKSAND AND WHALE SONGS
Sitting on the beach in Bermuda, I decide to make quicksand in a glass. First I partially fill the glass with sand, then add water until it just covers the sand, and stir hard. The result looks solid, like firm sand, but when I stick a finger in it, it sinks fast. Quicksand is just a suspension of sand in water, sand that’s become so saturated it pours like a milkshake—something temporary, not a permanent booby trap. Scary movies show people taking a wrong step, sticking deep, sinking agonizingly, and then suffocating. But that’s not likely, unless you thrash about so much in panic that your body goes under and you swallow, inhale water, and drown, as you might in any swimming pool or lake. Water is denser than the human body, as is sand; and the combination makes floating doubly easy. The body is buoyant, if allowed to be. I encountered quicksand once out West, on a ranch where I was working. A cow had wandered into it and panicked trying to escape, finally drowning. When we lassoed the carcass and dragged it out, the hide was coated in a rough porridge, and the eyelids looked as if they were sewn shut with burlap. I’m sorry now I didn’t wade in myself and test the waters, but at the time I listened to the cowboys’ warnings. Their land-savvy never failed me, and often delighted with its intuition and clarity. They’d seen frightened horses and cattle thrash until they disappeared in the mire, and had assumed that quicksand was aggressive and always deadly.
The hypnotic crash of the waves lulls me. Bending, I press my ear against the beach and hear the waves break even sooner. The vibrations travel about ten times as fast through the ground. Were I a Kalahari Bushman, I would be sleeping on my right side tonight, ear to the ground, so I could listen for the approach of a dangerous animal; my husband would sleep on his left side, and between us there would be a small fire to keep us warm while we slept, our ears cupping the earth. Or, if I were a character in one of the old cowboy movies, I might put my ear to the tracks and listen for the sound of the oncoming mail train. Because sound waves stay inside the metal rather than dispersing into the air, I’d hear the vibrations some distance away and know the payroll, or my sweetheart, would soon be arriving.
For hours, I’ve been watching the ocean for signs of humpback whales, whose songs were first recorded off Bermuda by Frank Watlington, and then later by Roger Payne. When I was a graduate student at Cornell, I attended a concert that Payne gave on his cello, accompanied by whale songs that boomed, yowled, gnashed, squeaked and thrubbed, filling the large auditorium with otherworldly music, and making my bones resonate from the low-down bass notes. This wasn’t the first time I’d heard whale songs; I had a record of Alan Hovhaness’s musical composition “And God Created Great Whales,” a piece haunted by a raga of sounds one doesn’t expect to add up to song. And yet the whales do sing. In fact, they croon. Lone, inactive males start to sing during winter, the breeding season, and continue their ballads until company arrives to interrupt them. Their songs often last fifteen minutes or so, and they repeat like carols over many hours. How structured the songs are, obeying the sort of rules one associates with classical music.
What’s more, the whales vary their songs. New phrases and elements arise each year, allowing the songs to evolve the way a language does. Each has half a dozen or so themes arranged in a certain order; if one theme is removed, the others still stay in their original order. When you sing “The Battle Hymn of the Republic,” you may choose to leave out the verse in which soldiers have built God an altar “in the evening dews and damps,” but you’ll keep the rest of the verses in the right order. Within the whale songs, there are repeating phrases that follow a carefully structured whale-song grammar. Perhaps the most impressive thing about all this is that the whales not only learn the complex language, but remember it from season to season. They arrive singing the song of the previous year, like coeds returning to school in September; when new phrases and slang evolve over the season, they remember them for the following year and abandon the lingo that’s out of date. They don’t sing by expelling air, as one might guess. Nor do they use their blowholes in a c
larinetlike way, as is sometimes shown in cartoons. Instead, they probably make their sounds by moving air around inside their heads. Like opera singers, they control their breathing very carefully, so as not to interrupt the fluency of the song. Most whales choose to do their breath-snatching in the same passages, and that allows researchers to listen for the breath spot and identify the singer.
Those who have dived among the singing whales describe the feel of the song as a drum pounding on the chest, or a pedal organ played inside the ribs. If you can’t be in the water with them, you can hear and feel them singing through the wooden boards of a boat. And not only humpbacks sing. White beluga whales have such a sweet, trilling voice that early whalers called them “sea canaries.” Now that their numbers are drastically reduced by pollution, the belugas are becoming the canaries in a liquid mine, warning us about the health of the oceans. Superstitious sailors used to hear the mournful songs of whales echoing up through the hulls of their ships, and were enraptured. Singing whales once inhabited the Mediterranean, and probably are the Sirens Greek myth says lured sailors to their doom on the rocks. Coming through the wood of a boat, their songs would be diffused in such a way that a sailor couldn’t localize them; the sounds would seem to be enveloping the ship in an eerie veil of song. Because whales ululate in sounds unique and varied, it’s a little difficult to describe their voices, but I once wrote the following sound poem after hearing a whale concert, and it may give a better sense of their songs:
WHALE SONGS
Speaking in storm language,
a humpback, before it blows,
lows a mournful ballad
in the salad-hill sea, murmurs
deep dirges; like a demiurge,
it booms from Erb to Santa Cruz,