Beasts can do so much more with their senses than us humans

‘An Immense World’ Review: Where Beasts Have Us Beat

Humans only see 1% of the colors a bird can see. What else are we missing?

Closeup of an eagle owl eye.PHOTO: JONATHAN KNOWLES/GETTY IMAGES

By Julie Zickefoose

June 17, 2022 11:56 am ETSAVEPRINTTEXT


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He digs, throwing clods of forest loam in a pelting shower behind him. He shoves his nose into a hole in a hollow log and inhales with long, shuddering breaths. He pulls back, exhales with a huff, reinserts his snout and again inhales the entire airspace of the log. My brindle cur is looking for traces of the chipmunk he knows is hiding within. Again and again he inhales, like an animated steam engine. From his wagging tail and perked ears, I conclude that this must be the best part of his day. I move on to find the showy orchis blooming in another valley. Soon he comes galloping, nose to ground, following my scent through each twist, turn and detour. He watches me as I prostrate myself to catch the fragrance of the diminutive flowers. Curtis can likely smell them yards away.


An Immense World: How Animal Senses Reveal the Hidden Realms Around Us

By Ed Yong

Random House

464 pages

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Umwelt is a term coined by the zoologist Jakob von Uexküll in 1909 to describe the sensory bubble that surrounds an animal—its perceptual world. It’s a world defined by the capabilities of the animal. Think about a dog’s Umwelt versus yours. His is dominated by sounds and odors; yours is more heavily visual. Your respective Umwelts are quite different, thanks to your differing abilities to perceive the stimuli swirling around you.

Ed Yong’s “An Immense World: How Animal Senses Reveal the Hidden Realms Around Us” is about entertaining possibility, stepping outside one’s own Umwelt and attempting to enter another’s—whether it be that of a tiny treehopper, mantis shrimp, dolphin, vulture or elephant. Mr. Yong, an award-winning science writer for the Atlantic magazine, warns at the outset that this won’t make for easy reading, but that’s only a goad to the science-minded. The result is a dense and dazzling ride through the sensory world of astoundingly sophisticated creatures. Who wouldn’t want to tag along on a field research trip or peek into the lab of a sensory biologist?


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Rex Cocroft studies plant-sucking treehoppers, social insects given to weird ornamentation like head cones and tail plumes. Clipping a simple amplifying microphone to a plant inhabited by throngs of treehoppers reveals that they create sonic vibrations with their abdomens, mooing like a herd of cattle. When Mr. Cocroft first shared these sounds with his mentor, the biologist Mike Ryan, Mr. Ryan said: “I was transported into a totally different world. . . . It was the coolest experience. It was sensory travel. I was in the same place, but stepping between these two really cool environments. It was such a stark demonstration of Uexküll’s idea.”



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The Umwelt concept, Mr. Yong writes, “tells us that all is not as it seems and that everything we experience is but a filtered version of everything that we could experience. It reminds us that there is light in darkness, noise in silence, richness in nothingness.” He goes on: “Stepping between Umwelten, or at least trying to, is like setting foot upon an alien planet. Uexküll even billed his work as a ‘travelogue.’ ”

“An Immense World” is rich with stories from lab and field, with lucid explanations of the mechanics behind sensory perception. There is more than enough mind-boggling science, with delightfully distracting footnotes on most pages and a whopping 45-page bibliography. Yet Mr. Yong’s storytelling will carry most readers through the thicket with ease.

Perception, history and transmissible culture combine in highly intelligent social animals. Infrasound is a recently discovered long-distance language for whales and elephants. With a microphone situated off Bermuda, scientists can hear blue whales singing in Ireland. In Kenya, elephants can synchronize meetings between groups separated by miles using low-frequency rumbles inaudible to us. They can also recognize the smell of those who hunt elephants: Offered piles of clothing worn by people of different ethnic groups, elephants discriminate and flee only from the scent of the Maasai people, for they alone will spear elephants.

Humans should be humbled by the perceptual abilities of other creatures. We have very good eyes, but it is possible that we see only 1% of the hundreds of millions of colors that a bird can discern. Birds see ultraviolet light; their world is suffused with myriad colors we can only imagine and will never be able to perceive. In the elegant synthesis that characterizes Mr. Yong’s writing, he points to the relationship between avian vision and impossibly gaudy poison dart frogs, whose “colors are so varied as to seem almost random, but there’s method to the visual madness.” Since those colors are intended as a warning, and are conspicuous to frog-predating birds, “an animal’s palette tells you whose eyes it is trying to catch. . . . Guided by evolution, eyes are living paintbrushes. Flowers, frogs, fish, feathers, and fruit all show that sight affects what is seen, and that much of what we find beautiful in nature has been shaped by the vision of our fellow animals. Beauty is not only in the eye of the beholder. It arises because of that eye.”

Most people are less than enamored of ticks, vampire bats and snakes, but they have something wild in common—infrared heat sensors. Ticks wear them at the tips of their feet; vampire bats and snakes have them in pits on their faces. A membrane in the snake’s pit senses a temperature rise of as little as 0.0001 degree Celsius; a rattlesnake can detect the body heat of a mouse three feet away. The pits function so much like eyes that it’s possible the snake sees infrared radiation as if it were another color.

It’s Mr. Yong’s task to expand our thinking, to rouse our sense of wonder, to help us feel humbled and exalted at the capabilities of our fellow inhabitants on Earth. This rich and deeply affectionate travelogue of animal sensory wonders ends with a plea to us—noisy, light-polluting anthropoid apes—to stop and consider others’ needs: for silence, for darkness, for space. Despite the stunning discoveries chronicled here, what we don’t know about these animals’ experience in the world we share is still virtually . . . everything.

Ms. Zickefoose is the author and illustrator of “Saving Jemima: Life and Love With a Hard-Luck Jay.”

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