An Immense World: How Animal Senses Reveal the Hidden Realms Around Us
Ed Yong 2022
“A moth will never know what a zebra finch hears in its song, a zebra finch will never feel the electric buzz of a black ghost knifefish, a knifefish will never see through the eyes of a mantis shrimp, a mantis shrimp will never smell the way a dog can, and a dog will never understand what it is to be a bat. We will never fully do any of these things either, but we are the only animal that can try.” Ed Yong
We spend the first formative years of our lives exploring and learning about our environment. Then, when we reach adulthood, we mostly think we have the world figured out- that we know what to expect from various situations, and where the dangers and rewards lurk. Because we're able to build these models of the world inside of our heads, we assume that they are reality and not just models, only to get fooled again and again all our lives when our models don't live up to the infinite vastness of reality out there. How do we sense the world around us? Are there just the five senses- sight, sound, taste, touch and smell, or are there more? Are there things we're not seeing, hearing, or smelling?
An Immense World by author Ed Yong takes an amazing in-depth look at the mysteries of our world through the eyes of animals, and it is a sobering and awe-inspiring trip through the many senses. Yong is a science journalist who has written one other best seller, I Contain Multitudes, as well as many articles in the Atlantic and various scientific publications. This book was nominated in several places as the best non-fiction book of 2022 and it's immense scope humbled me with my limited understanding of the senses.
One of the first revelations that I got from this book was how many scientists were working in this field. For decades, or even centuries, scientists have been studying species like the giant squid, naked mole rat, pit viper, electric eel, and barn owl to learn the secrets that only they can see from their unique perspectives. Why bother, some might ask. Seeing into the unique worlds of animals has added greatly to our knowledge base and aided in fields of medicine, business, and technology. This is difficult, painstaking work, and although Yong doesn't do the research himself, he certainly understands it, and presents it in a detailed and comprehensive way.
The word that Yong uses over and over is "unwelt", a scientific term for the unique perceptual world of each and every animal in existence. Our senses send vital information to the brain that can have life or death consequences, and each animal has evolved specific senses that maximize their survival chances. Because senses like sight, smell, and hearing require attention and energy that are in limited supply, there's no animal that can have it all. Better eyesight or hearing comes at the expense of other lesser-used senses, though many animals rely on a menu of senses just like humans do.
Dogs can hear things that humans can't hear, while chameleons can see simultaneously what's in front and behind them. Catfish are known as a "human tongue," because they have specialized taste receptors all over their body. And starfish are able to see out of multiple eyes at the end of each arm.
So how many senses are there? Yong points to 12, though there are probably more. In addition to the five basic senses, he considers color perception a sense, as well as pain reception, and heat detection. I would add to those the decidedly unscientific senses of dread, balance, psychic ability, and our emotional reactions to other people that we detect as friendly or threatening.
The more fascinating chapters of the book relate to senses that humans can't experience. Some animals can sense vibrations in the surface. Others can use echolocation to map out their environment. Over 350 species of fish can emit electric fields that sense their environment. And the most amazing one of all was the ability to sense magnetic fields from the earth itself, which explains the amazing abilities of sea turtles, salmon and migrating birds to know exactly where they came from and how to get back.
Yong ends the book with a plea to mitigate many of the sensory disturbances that modern civilization has created. Too much light from cities interferes with migrating birds and sea turtles. Too much noise interferes with the many signals that animals send to each other. And climate change- well that messes up all sorts of ecosystems with rising temperatures. The result has been a decrease in diversity across the globe, both in perceptual umwelts and in number of species, limiting the possibilities for new discoveries.
Having passed the midpoint of my life, I make an effort to keep learning new things and expand my "unwelt" as it were. Books like this only reinforce the reality that there is just so much about the world that we don't perceive, much less understand. The fact that animals have unique perceptual worlds applies to humans as well. Each of us has a unique perception and model of reality, and to assume that everybody should believe and think like we do is insanity. I can never know what it's like to walk in someone else's shoes, but at least trying and admitting that there is another way of seeing things increases humility, empathy, and learning, getting me a little closer to a better understanding.