An Exclusive Q&A with Ed Yong on An Immense World

What inspired you to write An Immense World? 

In a way, I was born to write this book. I’ve been fascinated by animals for as long as I can remember—my favourite childhood book was a college-level animal encyclopaedia that I in no way understood but utterly adored. But the specific idea for An Immense World came from my wife Liz Neeley, who has also long been fascinated by animals, aesthetics, and the intersection of the two. The idea was her gift to me, and the book, my gift to her. 

Imagination informs your book as much as science. Why are feats of imagination so important in understanding the natural world?

There will always be a gulf between our subjective experience of the world and another creature’s, and while science and technology can help to narrow that gulf, they can never fully bridge it. I can tell you how a bat uses its sonar, and by recording its calls, I can even come close to divining its intent. But I cannot tell you how it feels to be a bat—or an elephant, or a spider, or even another human. The only way to truly cross that gulf is through effortful feats of imagination. This is why An Immense World begins with a hypothetical scenario in which I ask readers to imagine a gym full of different creatures. This is a book about curiosity, about imagination, and about empathy—and I wanted people to be flexing all of those muscles from the first sentence. 

Traditionally, we are taught we have five senses. In your book, you categorise the senses into twelve chapters. Is it possible to fathom how many senses there actually are? 

We think there are five because of Aristotle, but he missed a few. Proprioception is how we know where our bodies are even without looking, and equilibrioception is how we balance or know which way is up. Dive into the rest of the animal kingdom, and things even get more complicated. Some animals have senses we lack: your humble backyard robin can sense the planet’s magnetic field and use it to navigate. Rattlesnakes can sense the body heat of their prey, using organs that connect to parts of the brain that process visual information. So is this heat sense a form of vision, or a form of touch, or something else entirely? And in some animals, senses we think of as distinct are fused: an octopus’s suckers might have a sense of taste-touch, in which they feel flavours or taste shapes. Counting the senses is a bit of a fool’s errand. What matters is thinking about how the different senses operate, their strengths and weaknesses, and how animals use them.  

In your book, you urge readers to ‘Save the Quiet, Preserve the Dark’. How can we go about tackling sensory pollution?

First, we have to realise it’s a problem. Light and noise just don’t seem like pollutants to us. Light, in particular, is synonymous with goodness, knowledge, and safety; it surely is nothing like plastics on a beach or chemicals billowing from a smokestack. But it very much can be when it shines at times and in places where it doesn’t belong. Light at night, and noise in quiet places, have pushed animals out of their habitats, drowned out the messages they send to each other, and waylaid them on their migrations—often with fatal results. But as ecological problems go, these are mercifully fixable ones. Plastics will continue despoiling the ocean even if all plastic production ceases tomorrow, but sensory pollution typically goes away at the flick of a switch. We just need the societal will to make that change. 

What is Umwelt, and what can it tell us about the sensory worlds of animals?

Umwelt literally means “environment” in German, but in this context, it’s not the physical environment around us. It’s the sensory environment—the sights, smells, textures, sounds, and other stimuli we can perceive. The concept behind the entire book is that our human Umwelt is radically different from that of other animals. We can’t perceive magnetic or electric fields, can’t see ultraviolet light, can’t hear the complexities in birdsongs. Other animals are limited in their own ways, so every species—and every individual—is perceiving just a thin sliver of the fullness of reality. This makes the Umwelt concept, in my mind, one of the most profound concepts in all of biology—at once humbling and expansive. It hints at the presence of the unfamiliar in the familiar, the magical in the mundane, the extraordinary in the ordinary. 

What are some of your favourite expressions of the varied and wonderful Umwelten in the animal world?

Dolphins are very popular and many people know they have a kind of sonar, sensing their environment by listening for the echoes of their own calls. But I was absolutely stunned to learn how sophisticated dolphin sonar is. They can sense buried mines, which military sonar cannot. They can tell the difference between cylinders that vary in thickness by the width of a hair, or those that contain liquids of slightly different densities. They can echolocate a hidden object, and that recognize that object on a screen. 

But I also love the Umwelten of lesser-known creatures. Scallops, far from just being pucks of garlic-sauteed meat, have rows of eyes along their shell that see the world in a way we can barely imagine. Treehoppers, tiny plant-dwelling insects that I guarantee you’ll have sat next to before, fill the plants of our gardens and parks with haunting melodies that we cannot hear. Black ghost knifefishes, star-nosed moles, golden orb-weaver spiders, horseshoe bats, mantis shrimps… they are the stars of the book, and I adore them all. 

Why was it important for you to appreciate creatures on their own terms, and not just to study them to better understand ourselves?

I think there’s a huge risk in appreciating the natural world through a purely transactional lens. Understanding the senses of other creatures can lead to new technological applications—we have telescopes based on lobster eyes. It can tell us about how our own brains work—many foundational aspects of modern neuroscience were discovered by studying electric fish. But these animals are not just fodder for brainstorming sessions, nor proxies for ourselves. They are magnificent and magical in their own right, and in large part because they are so different to us. That difference is crucial. Often, we appreciate the senses of animals when they exceed our own—sharks can smell blood blah blah blah—but I hope that readers of An Immense World will see why other species don’t have to break records to blow minds.  

Why is it misleading to assume that either animals experience pain exactly as we do, or do not experience pain at all?

The issue of animal pain is so morally and economically important that it often gets collapsed into the most simplistic of terms—does this group of creatures feel pain or not? But our knowledge of the other senses tells us that simple binaries are rare. Consider vision: animals see in a bewildering variety of ways, and there’s plenty of discussion about where simply ‘detecting light’ ends and actual ‘vision’ begins. Pain is like that. Some creatures recoil from harmful stimuli in a reflexive way that doesn’t involve any suffering, while we humans obviously feel the physiological and emotional sides of pain—and other animals probably fall somewhere in between, varying in their experience of pain as much as their experience of other sensory information. For example, squid clearly feel some form of pain but seem unable to localise it; it’s as if you stubbed your toe and your whole body became hypersensitive.  

And finally, if you could have any animal sense, which would you choose, and why? 

I have a corgi named Typo—he’s on the cover—and I’d love to know what he smells. It’s not the flashiest sense, but having it would help me understand him better, and bring us closer. And that, I think, is the whole point of An Immense World. Animal senses often feel like superpowers, but knowing about the Umwelt of another creature is our superpower—a skill that, as far as we know, is uniquely human, and one we should cherish and use.