"A sound as loud as a Blue whale makes can span half the world's oceans, which means two whales could [theoretically] send a signal around the globe in just over seven hours," explains Mark Fischer. These stunning visual renderings and the scope of what they represent give us valuable access to information about cetacean communication which would be impossible if presented in a different format.

"What motivated me to try this form of analysis is simple. The range of frequencies involved in cetacean sounds is extraordinary, from a low of 5-9Hz in the large mysticetes [baleen whales] up to 150 kHz in some of the odontocetes [toothed whales]. Standard, off-the-shelf spectral analysis software simply buckles under these demands." By slowly processing these enormous data files, Mark Fischer manages to reveal dark sonic landscapes which seem to echo the rippled undersea forms which generate them. Graphing frequencies which far exceed the capacity of human hearing, Fischer's wavelets provide rare glimpses of the wonders our ears are missing.

So began this work. There was a good place to start in "Marine Mammals and Noise," a good reference which basically maps the physics of sound in the world's oceans. But it turned out that cetaceans had an extraordinary range of sounds at their disposal. From lows around 10Hz for the large baleen whales, and highs over 100,000 cycles per second for Beluga and Spinner dolphins, these were really testing the resources I had.

Being spectrally challenged, I was motivated to take a look at another analysis tool called 'wavelets'. It had actually been around on paper since 1909. But it took a computer to make it useful. My first look was at blue whales, using clips I was able to find on the Web. By now, I have had a look at over a dozen species, from which I make both movies and stills.

I could speculate at length on what these pictures tell you, or might tell you, or infer, or whatever--it all kind of comes down to "what's a rainbow mean?", so let your mind do the wandering.