Tag Archives: Infrasound

Sound = Life

soundlife

photograph by Cheryl Merrill

Every second of every day unheard worlds tremble past my dim senses. Occasionally, when I’m in Africa, the air around me begins to thicken as an elephant’s vocalizations lift from infrasound into a register my ears can hear. Airquakes. Fractures and heaves of oscillating air. Another language, one without words, without speech.

I almost know infrasound. No more than two miles from my home freighters push through the deep waters of Puget Sound. On flat black nights the thump-thump of their propellers travels through water, through air, churns into my bed, my bones and into the lowest threshold of my hearing. It’s a mechanical throb, born in the bellies and boilers of machines, carried along rotating shafts which turn the metal blades of propellers, which slice through water like a dull knife hacking flesh. . . . . Whummp . . . whummp . . . whummp . . . . . . . . .

Out in the bay that fronts the town where I live, aggregates of barnacles coat docks and pilings and rocks. Their shells open and close, open and close, as feeding appendages catch food on the tides. Barnacle larvae hone in on the vibrations of feeding and settle in with their relatives so that they may easily exchange sperm and eggs with their kin. The sound of a large bed of barnacles can be heard for up to ten miles underwater.

Sound moves in waves similar to light waves. Light can be carried in a vacuum such as outer space but sound cannot. It needs a conducting medium. There’s a terribly silent universe beyond the top layer of earth’s atmosphere. It’s cold, breathless, without wind, without water, without life. On the moon our alien footfalls fell without sound into its dead dust. No one hears anything, unless you are in a spacesuit, listening to your own breathing.

Elephant Infrasound, Part Two

photograph by Cheryl Merrill

photograph by Cheryl Merrill

I almost know infrasound.

No more than a mile from my home huge freighters push through the deep, cold waters of Puget Sound. On flat black nights the thump-thump of their propellers travels through water, through air, churns into my bed, my bones, and the lowest threshold of my hearing. Born in the bellies and boilers of machines, the mechanical throb carries along rotating shafts that turn the metal blades of propellers, which slice through water like a dull knife hacking flesh: whummmp. ..whummmp…..whummmp.

Everything makes a sound when vibrations travel through a conducting medium, although we may not be able to hear it.

As Morula scuffs dirt, waves of air particles wash out in all directions. They reach my ear and vibrate my eardrum, which excites the three small bones of my middle ear: the hammer, anvil and stirrup. When the last little bone, the stirrup, takes up the vibration, it presses against fluid in my inner ear and creates a tiny sea of waves that tickle the hairs inside the spiral of my cochlea. The tickled hairs trigger auditory nerve cells that shoot electric signals to my brain.

Air, water and electricity in such a small space.

Large without, Morula’s ears are also large within. The bones of her inner ear are massive compared to mine. The combined weight of her hammer, anvil and stirrup totals just over a pound, compared to mine at two ounces. Her ear canal is eight inches long and her eardrum is about one and a half square inches. Maybe this doesn’t seem very big, but my eardrum is thinner than this paper and only one third of an inch square. You would need two hundred and fifty of my eardrums to create a stack an inch high.

Hum with your mouth closed. Now place your hands over your ears and hum again. The vibrations bypass your eardrums and are transmitted through your skull. Wavelengths tingle along your jaw line. Your bones are rattling.

Sounds are louder with a bigger collecting surface. Cup your hands behind your ears and listen as if you were an elephant.

Elephant Infrasound, Part One

Etosha Male photograph by Cheryl Merrill

Etosha Male
photograph by Cheryl Merrill

An excerpt from my book:

In 1984 whale researcher Katy Payne spent a week with eleven elephants at the Washington Park Zoo in Portland, Oregon, 170 miles south from my Pacific Northwest home. An acoustic biologist with fifteen years of experience studying the long and complex calls of whales, she was curious as to the kinds of sounds elephants make. Every waking hour of that week she listened and watched the elephants’ behavior at the zoo. She noticed that certain keepers elicited a positive response from the elephants, an intangible “thrill” in the air, like the rolling vibrations of thunder right before you hear them.

On her way back to Cornell University, while she thought about her observations, the throbbing of the airplane reminded her of a pipe organ she once heard. During a performance of Bach’s Passion According to St. Matthew, a shuddering filled the air as bass notes from the great pipes descended in a deep scale until sound disappeared – but the air still throbbed. Those same, strong, vibrations-without-sound had filled the air around the elephants in Oregon. Could they be communicating with infrasound, like whales?

Four months later, back at the zoo, Payne and fellow researcher Bill Langbauer set their recording equipment to its slowest speed. They mapped the elephants’ movements and timed changes in their behavior with the recordings. Working around the clock for an entire month, they recorded what sounded like snores, chirps, barks, rumbles and even moments of absolute silence.

Back at Cornell, the first tape Payne selected to review was during a time of silence, when there was a “thrill” in the air as a female elephant faced a concrete wall and a male elephant faced the same wall in an adjoining enclosure. The elephants were just three feet apart, but completely separated. Running the tape at ten times its normal speed, the researchers heard sounds emerge from silence – elephants carrying on an extensive conversation in infrasound, even when they couldn’t see each other.

To test this new theory of elephant communication, The Cornell research team rigged a double-blind experiment in Africa. An observation tower near a waterhole at Etosha National Park in Namibia was outfitted with video cameras and microphones. Miles from the waterhole, a mobile van roamed through the bush outfitted with broadcast speakers and tape recordings. The timing, location and content of the broadcasts were unknown to the observers at the tower.

One hot, dry afternoon, two male elephants, Mohammed and Hannibal, picked their way through the white calcareous rocks around the waterhole and paused for a drink. As soon as the two bulls arrived, the tower radioed the van. Selected at random, infrasonic estrous calls of a female elephant from Kenya were broadcast to the two bachelors in Namibia.

A female elephant needs to advertise as far and as wide as she can, since she is receptive to males for just a few days every estrus cycle. She repeats her calls over and over for up to forty-five minutes at a time. The calls can be heard for nineteen square miles – but only by other elephants.

Just seconds after the sound was sent, Mohammed and Hannibal froze, spread their ears and lifted their heads – twisting them side-to-side like scanning radar. Within two minutes the bulls set off. Half an hour later the pair strode past the van, looking for love in all the wrong places.

Infrasound: Looking for Love in All the Wrong Places

In 1984 whale researcher Katy Payne spent a week with eleven elephants at the Washington Park Zoo in Portland, Oregon, 170 miles south from my Pacific Northwest home.  An acoustic biologist with fifteen years of studying the long and complex calls of whales, she was curious as to the kinds of sounds elephants make.  She spent every waking hour at the zoo listening and watching the elephants’ behavior.  She noticed that certain keepers elicited a positive response from the elephants, an intangible “thrill” in the air, like the rolling vibrations of thunder right before you hear them.

On her way home to Cornell University, while she thought about her observations, the throbbing of the airplane reminded her of a pipe organ she once heard.  During a performance of Bach’s Passion According to St. Matthew, a shuddering filled the air as bass notes from the great pipes descended in a deep scale until sound disappeared – but the air still throbbed.  Those same, strong, vibrations-without-sound had filled the air around the elephants in Oregon.  Could they be communicating with infrasound, like whales?

Four months later, back at the zoo, Payne and fellow researcher Bill Langbauer set their recording equipment to its slowest speed.  They mapped the elephants’ movements and timed changes in their behavior with the recordings.  Working around the clock for an entire month, they recorded what sounded like snores, chirps, barks, rumbles and even moments of absolute silence.

Back at Cornell, the first tape Payne selected to review was during a time of silence, when there was a “thrill” in the air as a female elephant faced a concrete wall and a male elephant faced the same wall in an adjoining enclosure.  With the wall removed, the elephants would have been within three feet of each other.  Running the tape at ten times its normal speed, the researchers heard sounds emerge from silence – elephants carrying on an extensive conversation in infrasound, even when separated by concrete walls.

To test the theory, The Cornell research team rigged a double-blind experiment in Africa.  An observation tower near a waterhole at Etosha National Park in Namibia was outfitted with video cameras and microphones.  Miles from the waterhole, a mobile van roamed through the bush carrying broadcast speakers and tape recordings.  The timing, location and content of the broadcasts were unknown to the observers at the tower.

One hot, dry afternoon, two male elephants, Mohammed and Hannibal, picked their way through the white calcareous rocks around the waterhole and paused for a drink.  As soon as the two bulls arrived, the tower radioed the van.  Selected at random, infrasonic estrous calls of a female elephant from Kenya were broadcast to the two bachelors in Namibia.

A female elephant needs to advertise as far and as wide as she can, since she is receptive to males for just a few days every estrus cycle.  She repeats her calls over and over for up to forty-five minutes at a time.  The calls can be heard as far as two and a half miles away – over a range of nineteen square miles – but only by other elephants.

Just seconds after the sound was sent, Mohammed and Hannibal froze, spread their ears and lifted their heads – twisting them side-to-side like scanning radar.  Within two minutes the bulls set off.  Half an hour later the pair strode past the van, looking for love in all the wrong places.

Etosha Male, 1996, with streaming temporal gland, a sign of musth. Mohammed? Hannibal?

 

 

%d bloggers like this: