“An Immense World” by Ed Yong

Ed Yong’s new book, “An Immense World,” urges readers to break outside their “sensory bubble” to consider the unique ways that dogs, dolphins, mice and other animals experience their surroundings.

“I’ve often said that my beat is everything that is or was once alive, which covers billions of species, across basically the entirety of the planet’s history,” Yong says. “One thing I like about this particular topic — the sensory worlds of other animals — is that it, itself, though a singular, cohesive topic, is also the gateway to thousands of small wonders. There’s so much to learn about just in this one corner of biology.”

Spectacle floods into my eyes whenever I watch a wildlife documentary. A vortex of small fish is gradually picked off by waves of oceanic predators. Snakes chase after marine iguanas. Giraffes clash at sunset.

While the nature shows I grew up with were more like didactic lectures, their modern counterparts — all of which seem to have the word “Planet” in the title — have the bombast of summer blockbusters. Technological advances are partly responsible. Wild creatures are difficult to film, and when footage is fleeting and scarce, narration must provide the intrigue and flair that the visuals lack. But new generations of sophisticated cameras can swoop alongside running cheetahs at ground level, zoom in on bears cavorting on inaccessible mountainsides and capture intimate close-ups of everything from wasps to whales. Shots can now linger. Nature documentaries can be cinematic.

But in the process, they have also shoved the square peg of animal life into the round hole of human narratives. When animals become easier to film, it is no longer enough to simply film them; they must have stories. They must struggle and overcome. They must have quests, conflicts, even character arcs. An elephant family searches for water amid a drought. A lonely sloth swims in search of a mate. A cheeky penguin steals rocks from a rival’s nest.

Nature shows have always prized the dramatic: David Attenborough himself once told me, after filming a series on reptiles and amphibians, frogs “really don’t do very much until they breed, and snakes don’t do very much until they kill.” Such thinking has now become all-consuming, and nature’s dramas have become melodramas. The result is a subtle form of anthropomorphism, in which animals are of interest only if they satisfy familiar human tropes of violence, sex, companionship and perseverance. They’re worth viewing only when we’re secretly viewing a reflection of ourselves.

We could, instead, try to view them through their own eyes. In 1909, the biologist Jakob von Uexküll noted that every animal exists in its own unique perceptual world — a smorgasbord of sights, smells, sounds and textures that it can sense but that other species might not. These stimuli defined what von Uexküll called the Umwelt — an animal’s bespoke sliver of reality. A tick’s Umwelt is limited to the touch of hair, the odor that emanates from skin and the heat of warm blood. A human’s Umwelt is far wider but doesn’t include the electric fields that sharks and platypuses are privy to, the infrared radiation that rattlesnakes and vampire bats track or the ultraviolet light that most sighted animals can see.

The Umwelt concept is one of the most profound and beautiful in biology. It tells us that the all-encompassing nature of our subjective experience is an illusion, and that we sense just a small fraction of what there is to sense. It hints at flickers of the magnificent in the mundane, and the extraordinary in the ordinary. And it is almost antidramatic: It reveals that frogs, snakes, ticks and other animals can be doing extraordinary things even when they seem to be doing nothing at all.

While walking my dog, I see a mockingbird perched on a lamp post. With eyes on the side of its head, it has close to wraparound vision; while we move into our visual world, birds move through theirs. Their eyes also have four types of color-sensing cells compared with our three, allowing them to see an entire dimension of colors that we cannot; those colors, which are present on their feathers, allow male and female mockingbirds to tell each other apart even though they look the same to us. A mockingbird’s hearing differs from ours, too: It is so fast that when it mimics the songs of other birds, it accurately captures notes that fly by too quickly for our ears to make out.

I watch the mockingbird for about a minute, during which it belts out a few bars and flies off. But what more does it need to do? The baseline condition of its existence is magical. Its simplest acts of seeing, hearing and feeling are spectacular without spectacle.

By thinking about our surroundings through other Umwelten, we gain fresh appreciation not just for our fellow creatures, but also for the world we share with them. Through the nose of an albatross, a flat ocean becomes a rolling odorscape, full of scented mountains and valleys that hint at the presence of food. To the whiskers of a seal, seemingly featureless water roils with turbulent currents left behind by swimming fish — invisible tracks that the seal can follow. To a bee, a plain yellow sunflower has an ultraviolet bull’s-eye at its center, and a distinctive electric field around its petals. To the sensitive eyes of an elephant hawk moth, the night isn’t black, but full of colors.

Even the most familiar of settings can feel newly unfamiliar through the senses of other creatures. I walk my dog — Typo, a corgi — three times a day, passing the same streets and buildings that I’ve seen thousands of times. But though this urban landscape seems boring and stagnant to my eyes, its smellscape is constantly fascinating to Typo’s nose. He sniffs constantly, his nasal anatomy allowing him to continuously draw in odors even while exhaling. He sniffs the individual leaves of emergent springtime plants with utmost delicacy. He sniffs patches of dried urine left behind by the neighborhood dogs — the equivalent of a human scrolling through a social media feed. On every walk, there’ll be at least one moment when Typo grinds to a halt and excitedly explores a patch of sidewalk that looks nondescript but is clearly bursting with enthralling odors. By watching him, I feel less inured to my own life, more aware of the perpetually changing environment around me. Such awareness is a gift, which Typo gives to me daily.

These sensory worlds can be difficult, and sometimes impossible, for nature documentaries to capture (although some, like Netflix’s “Night on Earth,” make a valiant effort). No special effects can truly convey the wraparound nature of bird vision to the front-facing eyes of a human viewer or translate the wide spectrum of colors visible to a bird into the much narrower set that our eyes can see. Nonvisual senses are even harder for a visual medium to capture. You can play recordings of a whale’s song, but that doesn’t show what it means for whales to hear each other across oceanic distances. You can depict the magnetic field that envelops the planet, but that can’t begin to capture the experience of a robin using that field to fly across a continent.

In his classic 1974 essay, “What Is It Like to Be a Bat?” the philosopher Thomas Nagel wrote that the conscious experiences of other animals are inherently subjective and hard to describe. You could envision yourself with webbing on your arms or insects in your mouth, but you’d still be creating a mental caricature of you as a bat. “I want to know what it is like for a bat to be a bat,” Dr. Nagel wrote. Most bat species perceive the world through sonar, sensing their surroundings by listening for the echoes of their own ultrasonic calls. “Yet if I try to imagine this, I am restricted to the resources of my own mind, and those resources are inadequate to the task,” Dr. Nagel wrote.

Our own senses constrain us, creating a permanent divide between our Umwelt and another animal’s. Technology can help to bridge that chasm, but there will always be a gap. Crossing it requires what the psychologist Alexandra Horowitz calls “an informed imaginative leap.” You cannot be shown what another Umwelt is like; you must work to imagine it.

Watching modern nature documentaries has almost become too easy, as if I am being passively swept away by the torrent of vivid imagery — eyes open, jaw agape, but brain relaxed. By contrast, when I think about other Umwelten, I feel my mind flexing and the joy of an impossible task nonetheless attempted. In these small acts of empathy, I understand other animals more deeply — not as fuzzy, feathered proxies for my life, but as wondrous and unique entities of their own, and as the keys to grasping the true immensity of the world.

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