Friday, May 30, 2008


While on a trek through the elephant sanctuary near Thekkadi, after we had walked a couple of km, the guide asked us to stop, to remain absolutely silent and to start behaving like animals. Not what you imagine. What he was trying to tell us was that, once we were inside a forest, we should alert all our senses and watch out for small cues such as footmarks, or pick up sounds from different types of birds and animals. In a matter of a few minutes, he identified and pointed out the sounds from twelve different bird types, bearing exotic names such as blue-billed cockatoo, white-eyed mockatoo, red-tailed sockatoo, green-winged lockatoo, etc.

That was many years back. Today, if you were to go into the same forest, you will not be able to hear the cockatoo or the mockatoo, or for that matter the sockatoo and lockatoo. That’s because their characteristic sounds have been drowned by the racket made by human machinery.

Bernie Kraus, a field recording scientist, says that the natural sound of the world is vanishing. He'll be deep inside the Amazon, recording that cricket, but when he listens carefully he also hears machinery: The distant howl of a 747 or the dull roar of a Hummer miles way. (source)

Krause has a word for the pristine acoustics of nature: biophony. It's what the world sounds like in the absence of humans. But in 40 percent of the locations where Krause has recorded over the past 40 years, human-generated noise has infiltrated the wilderness. "It's getting harder and harder to find places that aren't contaminated," he says.

According to Kraus, in a biophony, animals divide up the acoustic spectrum so they don't interfere with one another's voices. So, a spectrogram of a wilderness recording, in which all the component noises are mapped according to pitch would look like the musical score for an orchestra, with each instrument in its place. No two species are using the same frequency. When they issue mating calls or all-important warning cries, they aren't masked by the noises of other animals.

But what happens when man-made noise — anthrophony, as Krause dubs it — intrudes on the natural symphony? Maybe it's the low rumble of nearby construction or the high whine of a turboprop. Either way, it interferes with a segment of the spectrum already in use, and suddenly some animal can't make itself heard. The information flow in the jungle is compromised.

So, if you are a male frog and you send out a mating call hoping to get a favourable response from a female of your species ( or vice versa to keep this blog gender neutral), you might not get any, as your croaking for all its sex appeal would have been jammed by the noise from a tractor nearby. Soon, no frogs and no Prince Charmings would be around.

All due to the anthrophonic acoustic imprint that you selfish human beings imposed on this planet.

Shame on you.


Usha said...

That is really interesting - the harmony and symphony in biophony and all the cacophony resulting from anthrophony.

dipali said...

Very interesting funda. God alone how many species are threatened by this insidious noise pollution of the planet.

Raj said...

usha, dipali, just remember to reduce your decibel level when talking1

Anonymous said...

We haven't left the sea either. Whales cannot communicate either, because of us.