How Animals Senses Reveal the Hidden World Around Us

From a Washington Post review by Sadie Dingfelder of the book by Ed Yong titled “An Immense World: How Animals Senses Reveal the Hidden World Around Us”:

A confession: I regularly get into arguments with children about animal facts. Often, they’re right and I’m wrong — I blame the educational cartoon “Wild Kratts.” But I may have wrested back the advantage, thanks to Ed Yong’s new book, “An Immense World: How Animal Senses Reveal The Hidden World Around Us.”

The premise of the book is that every species has access to a different slice of reality, and we humans can gain new perspectives by tapping into these alien worldviews. This powerful idea, first proposed by Estonian biologist Jakob von Uexküll in 1909, marinated for the better part of a century before catching on among modern scientists. In the last decade, research on other animals’ ways of perceiving and making sense of the world — also known as “umwelt” — has exploded. With “An Immense World,” Yong, a science journalist at the Atlantic, pulls together these findings with the promise of giving readers a scientifically based glimpse into what it would be like to be another animal.

“Through patient observation, through the technologies at our disposal, through the scientific method, and, above all else, through our curiosity and imagination, we can try to step into [other animals’] worlds,” Yong writes.

Yong proceeds sense by sense, from the familiar (sight, smell, taste), to the exotic (echolocation, electroreception, magnetoreception). He reveals a world thrumming with information to which humans are (perhaps thankfully) insensitive: Bats screaming at earsplitting decibels all night long, katydids playing plant stems like violin strings, flowers blazing with ultraviolet bull’s-eyes. Yong explains how these senses work — sometimes down to the biochemical level — and takes us on field trips to meet the scientists behind the findings, all while masterfully weaving these disparate threads into a single narrative rope. But, as I finished chapter after chapter, I couldn’t shake the feeling that we kept falling short of our promised destination: understanding what it’s like to be another animal.

This may be impossible. Perhaps you are familiar with the essay “What Is It Like To Be A Bat?” written in 1974 by philosopher Thomas Nagel. Nagel argues that even a scientist who learns everything there is to know about echolocation can never really imagine a bat’s experience, its umwelt. That’s because the bat has a lifetime of batty experiences that shape its worldview, not to mention a brain and a body utterly unlike our own. The best you can hope for, he argues, is to understand what it would be like for you, a human, to be a bat.

To my mind, this isn’t a real limitation. Even if you could get a bat to talk, he would probably have difficulty describing his lived, moment-to-moment experiences, just as you’d be baffled if someone asked you to describe your sensory and conscious experiences. (That is, unless you happen to be James Joyce.) This is because your umwelt is the only one you’ve ever known. To the extent that it’s possible, the only way to understand another animal’s umwelt is through comparison and imagination — two areas where Yong falls short.

Again and again, Yong tiptoes up to the precipice of another animal’s experience but never quite takes that final imaginative leap. For instance, when he meets up with cognitive scientist Alexandra Horowitz and her dog Finn, Yong contemplates Horowitz’s insights on her dog’s olfactory-focused experience: “Smells linger in a way that light does not, revealing history. The past occupants of Horowitz’s room have left no ghostly visual traces, but their chemical imprint is there for Finn to detect.”

This is all crucial information, but it doesn’t answer the underlying question: What is it like to be a dog? Since we humans are such visual creatures, a visual metaphor might help: Smells linger, so perhaps a dog’s “view” of the world is like a long-exposure photograph. Finn “sees” the ghostly, fading image of the dog who was here yesterday. He also has some X-ray vision (smells passing through surfaces), but he is a little nearsighted, because smells don’t travel as far as light.

Overall, Yong avoids using metaphors to other senses, but when he does indulge in them (or more often, when he quotes a scientist making that imaginative leap), these are the parts of the book I keep thinking about. On the question of what it’s like to echolocate like a bat or a dolphin, Yong posits that it might be like “touching with sound,” “It’s as if a dolphin is reaching out and squeezing its surroundings with phantasmal hands,” he writes.

What Yong never really gets to, however, are animals’ inner lives. As part of the umwelt revolution, scientists are exploring the ways other animals knit together sensory information into a coherent experience of the world. This, the squishy and contentious realm of comparative psychology and cognitive ethology, asks such questions as: Do dogs experience jealousy? (Yes!) Do cats understand cause and effect? (Maybe not!) Do dolphins have a sense of self? (Probably).

These findings stretch the imagination and force us to contemplate new ways of experiencing the world. What would it be like to feel no separation between yourself and your environment? How would you experience time if it slowed down or sped up depending on your body temperature? Are cats forever pushing things off shelves because the result never fails to be surprising?

Although “An Immense World” doesn’t quite plunge readers into other animals’ worlds, it does make a case for how much we humans miss — and misunderstand — when we fail to consider other animals’ worldviews. This, in itself, is a major achievement. Or, as Yong writes, “The task will be hard, as Nagel predicted. But there is value and glory in the striving.”

Sadie Dingfelder is a writer based in Washington.

Also see the New York Time review by Jennifer Szalai headlined “‘An Immense World’ Is a Thrilling Tour of Nonhuman Perception.”

How Animal Senses Reveal the Hidden Realms Around Us
By Ed Yong

A dolphin that echolocates a human in water can perceive not only the human’s outer shape but also what’s inside, including skeleton and lungs. Tree frog embryos — ensconced inside their unhatched eggs — can detect the vibrations of an attacking predator and release an enzyme from their faces that dissolves the casings that house them, allowing them to exit and escape.

That I found myself surprised at so many moments while reading “An Immense World,” Ed Yong’s new book about animal senses, speaks to his exceptional gifts as a storyteller — though perhaps it also says something regrettable about me. I was marveling at those details because I found them weird; but it turns out, if I try to expand my perspective just a bit, they aren’t so weird after all. One of Yong’s themes is that much of what we think of as “extrasensory” is “simply sensory.” A term like “ultrasound” is “an anthropocentric affectation.” The upper frequency limit for the average human ear may be a measly 20 kilohertz, but most mammals can hear well into the ultrasound range.

Yong offers these facts in a generous spirit, clearly aware that part of what will enthrall readers is discovering just how few of these facts many of us have known. I would have called the book “illuminating,” but Yong made me realize how much bias is baked into an adjective like this; humans, as a species, are “so relentlessly visual” that light for us has “come to symbolize safety, progress, knowledge, hope and good” — and so we have illuminated the planet to make it a more comfortable place for us, while making it less inhabitable for others. Artificial lights have been a fatal attraction for sea turtle hatchlings, migrating songbirds and some insects, steering them toward predators or disorienting them to the point of exhaustion.

Understanding this requires us to stretch the boundaries of our own “unique sensory bubble” in order to glean what we can of how other species experience their surroundings. Yong’s book is funny and elegantly written, mercifully restrained when it comes to jargon, though he does introduce a helpful German word that he uses throughout: Umwelt. It means “environment,” but a little more than a century ago the Baltic German zoologist Jakob von Uexküll used it to refer more specifically to that sensory bubble — an animal’s perceptual world.

The animals in Yong’s book are mostly nonhuman, but scientists are necessarily part of his story too. “A scientist’s explanations about other animals are dictated by the data she collects, which are influenced by the questions she asks, which are steered by her imagination, which is delimited by her senses,” Yong writes. The human Umwelt will necessarily shape how we apprehend other Umwelten. “An Immense World” inevitably refers to the philosopher Thomas Nagel’s foundational essay on this struggle, “What Is It Like to Be a Bat?”

But some humans might be more open-minded than others. A number of the sensory biologists Yong meets are perceptually divergent, seeing color differently or having difficulty remembering familiar faces: “Perhaps people who experience the world in ways that are considered atypical,” he writes, “have an intuitive feeling for the limits of typicality.”

“An Immense World” is organized by stimuli and their corresponding senses, beginning with smell and taste and extending to the ability of some animals — birds, bumblebees — to detect Earth’s magnetic field. When it comes to sight, there’s a trade-off between sensitivity and resolution; humans tend to have extraordinary visual acuity during the day but have a much harder time seeing at night, while animals with better night vision don’t register the crisp images at a distance that we do. “Senses always come at a cost,” Yong writes. “No animal can sense everything well.” The world inundates us with stimuli. Registering some of it is taxing enough; fully processing the continuous deluge of it would be overwhelming.

Still, an animal will use the various senses it has at its disposal to make sense of the world around it. A mosquito is attracted to the heat of warm-blooded hosts, but it will only attack if it first smells carbon dioxide — the sensation of heat without carbon dioxide isn’t a meal for a mosquito but a sign of possible danger. A researcher tells Yong that protecting humans from mosquitoes is a complicated undertaking, requiring her to consider multiple senses at once; the tiny insect has “a plan B at every point.”

Exchanges like this are an outlier in the book. Yong isn’t all that interested in the familiar question of how to exploit the senses of animals for human benefit; he wants us to try to understand how animals experience the world so that we can understand how animals experience the world. A mouse’s whiskers are for whisking, allowing it to scan the space around its head; what looks like a fly’s chaotic flight path turns out to reflect the finely attuned thermometers of its antennae, which steer it toward more comfortable temperatures. “Animals are not just stand-ins for humans or fodder for brainstorming sessions,” Yong writes. “They have worth in themselves.”

If there is a benefit to trying to imagine ourselves into the experiences of others, maybe it lies in the enormous difficulty of doing so; the limits of every species’ sensory bubble should serve as a reminder that each one of us has purchase on only a sliver of reality. Yong’s previous book, “I Contain Multitudes,” was an exploration of microbes and microbiomes; his writing for The Atlantic on the Covid-19 pandemic has frequently shown how the response to the crisis has been limited by our assumptions about the world and our place in it. Yong would like us to think more expansively — something that humans are, it turns out, equipped to do.

Thinking expansively would help us realize that nature’s true wonders aren’t limited to a remote wilderness or other sublime landscape — what Yong calls “otherworldly magnificence.” There is as much grandeur in the soil of a backyard garden as there is in the canyons of Zion. Recognizing the breadth of this immense world should spur in us a sense of humility. We just need to get over ourselves first.

Jennifer Szalai is a book critic for The New York Times. She was previously a columnist and editor for the Book Review. Her work has also appeared in Slate, New York, The New Yorker and Harper’s Magazine, where she was a senior editor until 2010.

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