Imagine walking through your yard or a nearby park and immediately the sounds of an orchestra of insects surround you.
Produced by the muscular movements of sap-feeding insects called leafhoppers, this imaginary soundscape emerges from vibrations that travel through the surface of plants. But it’s not at all like the familiar vocalizations of crickets or cicadas; it is rather something richer, more varied. Some sounds sound like songs, others sound like machines or musical instruments. Noise from even a single factory can be “as loud as a busy street”.
In A Huge World: How Animal Senses Reveal the Hidden Realms Around Us, Pulitzer Prize-winning science journalist Ed Yong explains that on a real walk instead of the one we imagined, humans couldn’t hear the music of leafhoppers without special equipment. In the company of scientists equipped with a laser vibrometer, a device that converts the vibrations of leafhoppers into sounds audible to the human ear, Yong manages to hear them in nature and in the laboratory. He is “stunned” by the “haunting and hypnotizing” sounds.
In this book which follows that of 2018 I Contain Multitudes, Yong writes with the perfect balance of scientific rigor and personal admiration as he invites readers to grasp something of how other animals experience the world. Communicating through surface vibrations is a very cool example that extends beyond leafhoppers to elephants and spiders, and to this fact on frogs: listening for vibrations entering eggs, frog embryos hatch quickly if a snake shows up with a hard bite, but ignores rain, wind, footsteps and even an earthquake. “They have agency,” Yong writes. “They have an Umwelt.”
Made famous by zoologist Jakob von Uexkull in 1909, the term Umwelt refers to the perceptual world experienced by each animal, a kind of very specific “sensory bubble”. When we walk our dog and he stops to smell all the other bushes or car tires, he picks up smells through his extremely sensitive nose that we pick up weakly or not at all. This is because humans and dogs have two different sensory bubbles, or Umwelten.
Yong explores the Umwelten of animals through chapters devoted, in addition to surface vibrations, to smells and tastes; light; Color; pain; Heat; contact and flow; sound; echoes; electric fields; and magnetic fields. The last two chapters then deal with how the senses work together and how a single species, ours, has disrupted animal senses through light and sound pollution. Gradually, the theme that Yong initially establishes takes shape and dimension as he writes that our own Umwelt seems natural, but it is only a way of feeling the world:
“That’s all we know, and so we easily confuse it with all there is to know. As a result, we tend to ‘frame the lives of animals according to our senses rather than theirs’. .
Yong is indifferent to the two motivations that drive scientists to study animal senses: to better understand our own senses and to apply knowledge of animal senses to produce new technologies. I found his insight welcome: “Animals are not just substitutes for humans or fodder for brainstorming sessions. They have value in themselves.”
Did you know that most insects are deaf? That the visual fields of cows, which may appear to be staring to the point of being indifferent to the environment, wrap around in space so that cows can see ahead, to the sides and behind them all at the same time? Or that the only sense that exists without some associated organ is magnetoreception, used by green sea turtles that “read” the Earth’s magnetic fields when they return to their nesting grounds on a small island after traveling 1 200 miles away?
Magnetoreception is a sense that humans (apparently) rarely use, while some animal sensory abilities are not available to us at all. Some electric fish “can determine the position, size, shape, and distance of” nearby objects by creating “electric images…from patterns of voltage dancing across” their skin. Dolphins sail by listening to the echoes of their clicks:
“If a dolphin echolocates you, it will sense your lungs and skeleton. It can probably detect shrapnel in war veterans and fetuses in pregnant women. It can almost certainly tell different [fish] species apart depending on the form of [their] air bladders.”
(That’s not to say humans can’t echolocate at all. Yong walks with Daniel Kish, who had both eyes removed in his early childhood due to aggressive cancer. When Kish walks around, does biking or hiking, it emits clicks that allow it to sense, through echoes, the location and shapes of everything from houses to cars to trees.Yet even the best human echolocators don’t can’t do what dolphins can do.)
My admiration for the book is, well, immense. I wonder about a choice Yong makes, evident in some examples above and in sentences like this: “A dolphin is an echolocator that clicks with its nose and listens with its jaw.” Here, the word “it” is better suited to an object than to a living and thinking being, the same with the word “it”. An alternative phrase, “Dolphins are echolocators that click with their noses and listen with their jaws,” strikes me as more aligned with Yong’s obvious respect for animals as precious beings in their own right. As Scott Simon wrote last year for NPR, “If a cat or dog shares your home, I’m assuming you’re not referring to the four-legged family member licking your face, napping on your lap, sleep on your bed…like ‘it’.” Full disclosure: I was a signatory to a letter described by Simon asking the media to use more animal-friendly pronouns.
With our insistence on bright lights disrupting dark skies and a lifestyle that produces incessant noise from all manner of machinery, including on land, air and sea routes, we are seriously impairing other animals’ ability to use their senses correctly. But there is hope, because “sensory pollution is an ecological gimme”: conditions immediately improve when lights or motors are turned off or adjusted. By turning off lights that interfere with the paths of migratory birds and sea turtles, and dampening noise through the use of acoustic barriers, we can protect the glorious Umwelten all around us.
Like thousands of others, I have relied throughout COVID-19 on reporting from Yong to Atlantic as he opened up the rapidly changing world of pandemic science. Now with A huge world, Yong sheds light on a host of other animal sensory worlds that co-exist with our own, and how we can protect them. He has synthesized and convincingly presented a spectacular amount of scientific information to do this, which looks easy along the way. But it’s not easy at all. It is a magnificent achievement.
Barbara J. King is Distinguished Biological Anthropologist at William & Mary. Animals’ Best Friends: Bringing Compassion to Animals in Captivity is his seventh book. Find her on Twitter @bjkingape