Ed Yong – An Immense World: Book Review & Audio Summary

Book Info

• Book name: An Immense World: How Animal Senses Reveal the Hidden Realms Around Us
• Author: Ed Yong
• Genre: Science & Technology
• Pages: 416
• Published Year: 2022
• Publisher: Random House
• Language: English
• Awards: Winner of the 2022 Pulitzer Prize for General Nonfiction

Audio Summary

Synopsis

In An Immense World, Pulitzer Prize-winning science writer Ed Yong takes readers on an extraordinary journey through the sensory experiences of animals. Far beyond our familiar five senses, the animal kingdom employs magnetoreception, echolocation, electroreception, and countless other perceptual abilities we can barely comprehend. From sea turtles navigating by Earth’s magnetic fields to electric eels generating lethal voltage, from bats painting sonic pictures to ants communicating through intricate chemical signals, Yong reveals how different creatures experience reality in profoundly alien ways. This groundbreaking exploration challenges our human-centered view of the world and opens our eyes to the hidden realms that exist all around us, forever changing how we understand our place in nature.

Key Takeaways

• Animals possess sensory abilities far beyond human comprehension, including magnetoreception, electroreception, and chemical communication that reveal entirely different versions of reality
• Human senses, while sharp in some areas, represent just a tiny slice of possible sensory experiences—we’re essentially living in a limited perceptual bubble
• Understanding animal senses can help us become better stewards of the environment by recognizing how human activities like artificial light and noise pollution disrupt animal perception
• Humans have untapped sensory potential, as demonstrated by people who’ve learned to echolocate, suggesting our perceptual abilities are more flexible than we assume
• Each species lives in its own unique sensory world (what scientists call an “Umwelt”), making the planet home to countless overlapping but distinct realities

My Summary

Beyond Our Five Senses: A New Way of Seeing Reality

I’ll be honest—when I first picked up Ed Yong’s An Immense World, I thought I had a pretty good handle on animal senses. Sure, I knew dogs could smell better than humans and eagles had sharper vision. But I wasn’t prepared for how completely this book would shatter my understanding of reality itself.

Yong, a science journalist who won the Pulitzer Prize for his COVID-19 reporting, has crafted something truly special here. This isn’t just another nature book listing fun facts about animals. It’s a philosophical journey that forces you to confront a humbling truth: the world you experience every day is just one version of reality among countless others.

The central concept Yong explores is the “Umwelt”—a German word coined by biologist Jakob von Uexküll that describes each animal’s unique perceptual world. Every creature on Earth lives in its own sensory bubble, detecting stimuli we can’t even imagine and completely missing things that seem obvious to us. It’s like we’re all living in the same physical space but experiencing entirely different dimensions.

The Visual World: More Than Meets the Eye

Let’s start with sight, since it’s the sense most humans rely on heavily. We’re trichromats, meaning we have three types of color-detecting cones in our eyes. This allows us to see a rich spectrum of colors that shapes everything from our art to our traffic signals to the way we choose ripe fruit at the grocery store.

But here’s where it gets interesting: many animals are dichromats with only two cone types, like dogs and horses. When I learned this, I immediately thought about my neighbor’s golden retriever who completely ignores the bright red ball in green grass. Now I understand why—to him, they’re probably nearly the same shade! Yong explains that we can simulate dichromatic vision using photo editing software, which gives us a glimpse into their world of grays, yellows, and blues.

The really mind-bending part? Some animals have four, five, or even more cone types. Mantis shrimp, for example, have sixteen types of photoreceptors. Sixteen! We can’t even begin to imagine what colors they perceive because our brains literally don’t have the hardware to process that information. It would be like trying to explain the color red to someone who’s been blind since birth.

But having more cones doesn’t necessarily mean experiencing the world the way we do. Yong introduces us to Daphnia water fleas, tiny creatures that detect different wavelengths of light but don’t construct visual scenes like we do. For them, ultraviolet light simply triggers an instinct to swim away (because it indicates dangerous sunshine), while green and yellow wavelengths prompt them to swim closer (because those colors mean food). They’re not “seeing” in any way we’d recognize—they’re just responding to light as another form of stimulus, like we might react to temperature or pain.

This really made me reconsider what “seeing” even means. We assume vision always creates a picture of the world, but that’s just our human bias showing.

Echolocation: Seeing with Sound

One of the most fascinating sections of the book explores echolocation—the ability to navigate and identify objects using sound waves. We typically associate this with bats and dolphins, but Yong reveals that humans can learn this skill too.

The story of Daniel Kish absolutely floored me. After losing both eyes to cancer before his second birthday, Kish developed the ability to echolocate using tongue clicks. He can now walk around neighborhoods, identifying where houses end, distinguishing driveways from yards, and even ducking under low-hanging tree branches—all without sight in the traditional sense.

What makes Kish’s story so valuable is that he can articulate what echolocation feels like from a human perspective. He describes sensing objects primarily through their density and texture rather than their visual appearance. His clicks produce lower-frequency sound than bats use, so his resolution is blurrier—edges aren’t crisp, and small objects against large backgrounds can be difficult to detect.

Reading about Kish made me want to try echolocation myself. I actually spent an embarrassing amount of time clicking my tongue in my garage, trying to sense the difference between my car and the open doorway. I can’t say I was successful, but it gave me a profound appreciation for how much practice and neural rewiring must be required to develop this skill.

For bats, echolocation is so refined they can snatch flying insects out of midair and navigate through obstacle courses of hanging chains. Dolphins can recognize two-dimensional pictures of objects they’ve previously examined only through sonar. These abilities reveal that “seeing” doesn’t require eyes at all—it just requires any sensory system that can build a spatial model of the environment.

What This Means for Human Potential

The echolocation discussion raises profound questions about human sensory potential. If people like Daniel Kish can learn to echolocate, what other latent sensory abilities might we possess? Are we limiting ourselves by assuming our five traditional senses are all we have? In my work reviewing books on human potential and neuroscience, I’ve encountered research suggesting our brains are far more plastic and adaptable than we typically assume. Yong’s exploration of echolocation provides compelling real-world evidence for this plasticity.

The Chemical World: A Universe of Scents

When Yong asks readers to name an animal that excels at smelling, most of us probably think of dogs or maybe elephants. I certainly didn’t think of ants. But these tiny insects possess extraordinarily sensitive chemical detection abilities that put our noses to shame.

Ants navigate their entire social world through pheromones—chemical signals used to communicate within a species. They leave scent trails to mark food sources, identify colony members, and summon reinforcements to overwhelm prey. Their reliance on smell is so complete that they can be fooled by the right scent, even when visual information contradicts it.

Yong shares the remarkable example of red worker ants caring for blue butterfly caterpillars because they smell exactly like ant grubs, despite looking completely different. Imagine being so scent-driven that you’d care for a baby giraffe thinking it was a human infant, simply because it smelled right. That’s how different the ant’s perceptual world is from ours.

This section made me think about my own neighborhood differently. I used to see the ant trails on my sidewalk as simple lines of insects marching along. Now I understand they’re following invisible chemical highways, reading information we can’t detect at all. There’s an entire communication network happening right under our feet, completely imperceptible to human senses.

The Complexity of Chemical Communication

What strikes me most about chemical communication is how information-rich it can be. A single pheromone might convey not just “food here” but also information about food quality, distance, and even urgency. Some animals can detect individual molecules, allowing them to track scents across vast distances or identify specific individuals by their unique chemical signature.

This has practical implications for how we design our environments. Air fresheners, cleaning products, and pesticides don’t just affect what we smell—they potentially disrupt crucial chemical communication networks for countless species. It’s another reminder that our actions have consequences we can’t even perceive.

Magnetoreception and Electroreception: Senses Beyond Human Experience

While the book summary I worked from doesn’t fully elaborate on these senses, Yong dedicates significant attention to abilities that are completely alien to human experience. Magnetoreception—the ability to sense Earth’s magnetic field—is used by migratory birds, sea turtles, and even spiny lobsters for navigation.

Think about how revolutionary GPS technology seemed when it became widely available. Now imagine having that capability built into your nervous system from birth. That’s essentially what magnetoreception provides. These animals can sense invisible field lines that permeate the entire planet, using them as a built-in compass for journeys spanning thousands of miles.

Electroreception is equally mind-blowing. Electric eels can generate enough voltage to kill a horse, but many fish use much subtler electrical fields for navigation and communication. They essentially create an electrical bubble around themselves and sense distortions in that field caused by nearby objects. It’s like having radar, but electrical.

These senses are so far outside human experience that we didn’t even know they existed until relatively recently. How many other sensory modalities might be out there, still waiting to be discovered? This question keeps me up at night in the best possible way.

The Modern Context: Why This Matters Now

You might be wondering why understanding animal senses matters beyond pure curiosity. Yong makes a compelling case that this knowledge is crucial for conservation and environmental stewardship in our increasingly human-dominated world.

Consider light pollution. For humans, a brightly lit city might seem safe and welcoming. But for nocturnal animals that navigate by starlight, or sea turtle hatchlings that orient themselves by finding the brightest horizon (which should be the ocean reflecting moonlight), artificial lighting creates deadly confusion. Baby turtles crawl toward beachfront hotels instead of the ocean, and migratory birds crash into illuminated buildings by the millions.

Similarly, noise pollution doesn’t just annoy animals—it can completely disrupt species that rely on sound for navigation, finding mates, or detecting predators. Whales and dolphins that use echolocation can become disoriented by underwater noise from ships and sonar. Birds that communicate through song can’t hear each other over traffic noise, affecting their ability to defend territories and attract mates.

In my own life, reading this book has changed how I think about my environmental impact. I now use motion-sensor lights instead of leaving exterior lights on all night. I’ve become more conscious of noise levels, especially during dawn and dusk when many animals are most active. These are small changes, but they come from a place of understanding that my sensory comfort might be another creature’s sensory nightmare.

Climate Change and Sensory Disruption

Climate change adds another layer of complexity. Many animals time crucial activities—migration, reproduction, hibernation—based on environmental cues they sense. As temperatures shift and seasonal patterns become less predictable, these cues can become unreliable. A bird might arrive at its breeding grounds too early or too late because the temperature signals it relied on no longer correspond to food availability.

Understanding animal senses helps us predict and potentially mitigate some of these impacts. It’s not just about saving individual species—it’s about preserving the intricate sensory relationships that make ecosystems function.

Practical Applications: Changing How We Interact with the World

Beyond environmental considerations, understanding animal senses has practical applications in our daily lives. Here are some ways this knowledge has changed my perspective and behavior:

Pet ownership: Knowing that my friend’s dog sees a different color spectrum has made me rethink how I choose toys for him. Blue and yellow toys show up much better against grass than red ones do. I’ve also become more aware that his sense of smell is his primary way of experiencing the world, so I let him sniff more on walks instead of constantly pulling him along.

Garden design: I now plant flowers that reflect ultraviolet light in patterns visible to pollinators but invisible to me. Many flowers have UV “landing strips” that guide bees to nectar. Understanding this has made me appreciate that my garden exists in multiple sensory dimensions simultaneously.

Wildlife observation: When I’m hiking or birdwatching, I think more carefully about how animals might perceive me. I avoid wearing bright white clothing (which might be highly visible in UV spectrum to birds) and move more slowly to avoid triggering motion-detection systems that many animals rely on.

Technology design: As someone who reviews books on technology and innovation, I’ve started thinking about how we might design devices that account for animal senses. Could we create wind turbines that emit sounds warning bats away? Could we design glass that’s visible to birds while remaining transparent to humans?

Empathy and perspective-taking: Perhaps most importantly, understanding that other creatures experience profoundly different realities has made me more humble and empathetic generally. If I can’t even imagine what a mantis shrimp sees, maybe I should be more open to the possibility that other humans experience the world differently than I do too.

Strengths and Limitations of the Book

Yong’s greatest strength is his ability to make complex scientific concepts accessible without dumbing them down. His writing is engaging and often poetic, helping readers not just understand but feel the wonder of these alien sensory worlds. The book is meticulously researched, drawing on hundreds of scientific studies, yet it never feels like a textbook.

I particularly appreciated how Yong centers the scientists doing this research, especially those from underrepresented groups. He shows science as a human endeavor, complete with false starts, lucky breaks, and passionate individuals dedicating their lives to understanding animal perception.

However, some readers might find the book’s breadth somewhat overwhelming. Yong covers so many species and sensory systems that it can occasionally feel like drinking from a fire hose. I found myself wishing for slightly deeper dives into fewer topics, though I understand the author’s desire to showcase the full diversity of animal senses.

Additionally, while Yong touches on animal cognition, he largely avoids the thorny question of animal consciousness and subjective experience. Does a bat “experience” its echolocation the way we experience sight? Does it feel like anything to be an ant following a pheromone trail? These philosophical questions remain largely unexplored, though perhaps that’s beyond the scope of a single book.

How This Book Compares to Similar Works

For readers interested in animal cognition and perception, An Immense World pairs well with several other recent books. Frans de Waal’s Are We Smart Enough to Know How Smart Animals Are? focuses more on intelligence and problem-solving, while Yong concentrates on sensory experience. Together, they provide a comprehensive picture of animal minds.

Peter Godfrey-Smith’s Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness explores similar themes but focuses specifically on cephalopods and the evolution of consciousness. Godfrey-Smith’s book is more philosophical, while Yong’s is broader in scope.

Sy Montgomery’s books, like The Soul of an Octopus, offer more personal, narrative-driven explorations of animal minds. If you prefer memoir-style nature writing, Montgomery might be your entry point. But if you want comprehensive scientific coverage with strong writing, Yong is hard to beat.

What sets An Immense World apart is its systematic exploration of sensory modalities across the entire animal kingdom. Rather than focusing on one species or one type of intelligence, Yong provides a framework for understanding how perception itself shapes reality. It’s ambitious in the best possible way.

Questions Worth Pondering

After finishing this book, I’ve been mulling over several questions that I’d love to discuss with other readers. If humans can learn to echolocate, what other sensory abilities might we develop with training? Could we learn to detect magnetic fields or electric currents? Some research suggests humans might have latent magnetoreception abilities—we just don’t know how to consciously access them.

Another question: How should understanding animal senses change our moral obligations toward other species? If we know that artificial light causes measurable suffering and death for countless creatures, do we have a responsibility to change our behavior? Where do we draw the line between human convenience and animal welfare?

I’m also curious about how this knowledge might influence art and creativity. Could we create music or visual art that somehow represents these alien sensory experiences? Some artists are already experimenting with representing UV patterns or translating echolocation into visual or tactile forms.

A Book That Changes How You See Everything

I’ll admit that An Immense World has fundamentally changed how I move through the world. I find myself pausing on walks, trying to imagine what the dog passing by is smelling, or what the robin overhead is seeing. I look at my backyard pond and think about the electric fields fish might generate, or the chemical signals frogs might be exchanging.

This book is a masterclass in perspective-taking. It’s a reminder that our human experience, as rich as it feels, is just one tiny slice of reality. There are entire dimensions of existence happening all around us, all the time, that we’re completely blind to. That’s both humbling and exhilarating.

For anyone interested in nature, science, philosophy, or just understanding the world more deeply, I can’t recommend this book highly enough. It’s the rare science book that’s both intellectually rigorous and emotionally moving. Yong has given us a gift: a new way of sensing the immense world around us.

I’d love to hear from other readers who’ve explored this book. What surprised you most? Has it changed how you interact with animals or think about the environment? Drop your thoughts in the comments—I’m always eager to discuss how books like this reshape our understanding of the world we share with countless other sensing creatures.