Of all Leonardo Da Vinci’s great ideas, one of my favorites is one of his simplest. No diagrams, no assembly required, just a simple re-purposing of an everyday item—the canoe paddle. He suggested if we put its blade into water and then pressed our ear against its shaft, we could hear the sounds of aquatic life. Once again, Leonardo was way ahead of it’s time. Not only did this idea pre-date sonar, it predated the belief that the sea was worth listening to.
In a study published in 2009, a group of biologists in Australia described a rich “vocal repertoire” of vocalizations among long-necked freshwater turtles, Chelodina oblonga. The list of sounds included “clacks, clicks, squawks, hoots, short chirps, high short chirps, medium chirps, long chirps, high calls, cries or wails, hooos, grunts, growls, blow bursts, staccatos, a wild howl, and drum rolling.” Of course, to assume that other turtles—including any of the 15 species in our beloved Santa Fe—have similar “vocabulary” is to enter dangerous and highly unscientific territory.
Non-scientifically speaking, it seems unlikely that one species of turtle is chatting away in a language of 17 unique sounds and others are mute. I’d love to think that that our own turtles occasionally throw back their heads and “howl,” in decibels we can’t hear—their own version of the alligator bellow—or that on nights when the moon is just so, and the owls assure them there are no humans in earshot, they crowd onto logs and launch into fevered rounds of “drum rolling.”.
Unlike turtle talk, there’s nothing subtle about alligator bellows. When William Bartram described alligators arching their back and “making the earth tremble with their thunder,” few people believed him. It would be decades before this phenomenon was confirmed by others. Both male and female gators bellow without regard to the hour of day or night or if they’re on land or in water. The only quiet time is winter. It’s assumed to be a general announcement of the gator’s presence, but this too is only speculation.
The most spectacular bellowing is the “water dance,” done only by the males. In this display, the male rears his head, lifts his tail and then powerfully contracts his body, causing it to vibrate. If the gator is in water, the contraction causes water between the scales of its back to spray up in a misty fountain. Diane Ackerman described it beautifully, in “A Natural History of the Senses,” as “frying diamonds.”
To be clear, it’s not the realization that marine animals make sounds that’s new, it’s the notion that they use these sounds for communication. In the days of wooden ships, sailors could hear the eerie sounds of whale’s songs emanating up from the ships hull. Some people speculate that this was the origin of the myth of Sirens, the legendary beauties who sang enchanting songs from the rocky shore and caused ships to come close and crash.
To date, researchers have identified over 1,000 fish that make sounds.
Minyard Connor savors his weightlessness. He’s oblivious to the gentle whitecaps churning thirty feet above him. He’s been down for over a minute without an air tank, listening and watching. In his years as a free diver, Minyard has learned that seas are noisy places. He recognizes the calls and chirps of the fish he’s hired to find by men like the one whose fishing line is now attached to his spear; the one who is likely swilling his fifth Bud Light in the boat overhead. Minyard knows the sounds, but he doesn’t know their meanings. He’s okay with that. Down here, at least, he’s not expected to understand.
There are a few things the researchers have sorted out. For instance, it’s mostly male fish that make sounds. In those cases where a purpose has been determined, it’s usually for mating and courtship. Butterfly fish whisper, Seahorses make a click by tossing back their heads, streaked gurnards and rockfish growl. As we paddle the waters of Chassahowitzka and Suncoast Keys this weekend, we’ll listen for the “bubble and thud” of eels, the “cronk” of sea robins, the “grunting” of toadfish and the “umph” of bass.
The list of species that make the water hum with their chatter is diverse. The one thing most of them have in common is the absence of external ears. Instead they have an assortment of pressure-detecting organs. Fish have lateral lines on their sides, blind cave fish have neuromasts on their heads, manatees have a depression on their cheek, and so on, but none of them have ears. And, therein lays the key to our own deafness in water. No matter how hard Minyard listens, he’ll never hear more than a fraction of the conversations buzzing around him, any more than we can hear the radio waves in our own terrestrial world of light air. We go about our days clueless that the air around us is full of "Lake Wobegone Days," until we turn on our high-tech sensory device—our radio—and find Garrison Keillor in full stride. The only humans who will ever enjoy the melodies and impassioned conversations that constantly vibrate our planets waters will be marine researchers with their gadgets. Even then, it will be a strange opera—beautiful music and babel.
As for using paddles as listening devices, it appears that in this instance, Da Vinci had an idea better suited to poets than engineers. But, I’m okay with that. I find comfort in knowing that besides holding up my hat, my ears allow me to hear such beautiful sounds as bird song, the wind in palms, fireside stories of people like my friend Minyard, and the finest of all river sounds, the blip, swish, plink of a canoe paddle doing the task it was designed for.