Deep: Freediving, Renegade Science, and What the Ocean Tells Us About Ourselves

by James Nestor

Coda clicks, the focus of Schnöller’s work, are used only during socializing and are significantly different from clicks used to aid perception and navigation. They sound unremarkable to the human ear—something like the tack-tack-tack of marbles dropped on a wood table. But when the clicks are slowed down and viewed as a sound wave on a spectrogram, each reveals an incredibly complex collection of shorter clicks inside it. Inside those shorter clicks are even shorter clicks, and so on. The more closely Schnöller focused in on a click, the more detailed it became, unfolding on his computer screen like a Russian nesting doll. An average click lasts anywhere from twenty-four milliseconds (thousandths of a second) to seventy-two milliseconds. Inside these clicks are a series of microclicks, which themselves are separated by microseconds, and so on. All these tiny clicks inside the coda are transmitted at very specific and distinct frequencies. There could be even shorter, organized click patterns within these microclicks, but Schnöller’s machines—which record at 96,000 Hz, the highest speed available on most modern audio equipment—aren’t fast enough to process them. Schnöller tells me that sperm whales can replicate these clicks down to the exact millisecond and frequency, over and over again. They can also control the millisecond-long intervals inside the clicks and reorganize them into different structures, in the same way a composer might revise a scale of notes in a piano ...