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Secret Worlds: The Extraordinary Senses of Animals
Martin Stevens explores the extraordinary variety of senses in the animal kingdom, and discusses the cutting-edge science that is shedding light on these secret worlds.
Our senses of vision, smell, taste, hearing, and touch are essential for us to respond to threats, communicate and interact with the world around us. This is true for all animals - their sensory systems are key to survival, and without them animals would be completely helpless. However, the sensory systems of other animals work very differently from ours. For example, many animals from spiders to birds can detect and respond to ultraviolet light, to which we are blind. Other animals, including many insects, rodents, and bats can hear high-frequency ultrasonic sounds well beyond our own hearing range. Many other species have sensory systems that we lack completely, such as the magnetic sense of birds, turtles, and other animals, or the electric sense of many fish. These differences in sensory ability have a major bearing on the ways that animals behave and live in different environments, and also affect their evolution and ecology.
"What is it like to be a bat?", the philosopher Thomas Nagel famously asked concerning consciousness. For biologist Martin Stevens, the question forms the starting point of an exploration of animal senses. How indeed does a bat - or an owl, a bee, or a platypus - experience the world? Very differently to us humans, as we discover.
Many animals experience a world far richer in sight, sound, and smell and interact with each other in ways we simply don’t pick up, and which continue to surprise researchers. Who would imagine that rats and mice sing complex songs while courting; or that the humble dung beetle relies on light from the Milky Way above for guidance as it carries its precious cargo away from competitors? The world must show so much more colour to many birds, with four types of cones in their eyes instead of our three, and the ability to see into the ultraviolet. And that’s just considering the senses we share. What of those we have no inkling of - like the electric fields sensed by so many animals; or the magnetic maps used by migrating birds, and by sea turtles to find a current and return after many years to the shore where they hatched?
In this enthralling account, we learn not only of the wonder of animal senses, but how they work and how scientists go about investigating them. And, throughout, we consider how these senses came to be. For evolution is at the root of it all, as Stevens explains. Senses arose to enable animals to catch prey, to hide, and to mate more effectively, usually honed through fierce competition and arms races with predators. The result, over millions of years, is a wondrous panoply of ways of experiencing the world, against which our own senses often pale into insignificance.
Our senses of vision, smell, taste, hearing, and touch are essential for us to respond to threats, communicate and interact with the world around us. This is true for all animals - their sensory systems are key to survival, and without them animals would be completely helpless. However, the sensory systems of other animals work very differently from ours. For example, many animals from spiders to birds can detect and respond to ultraviolet light, to which we are blind. Other animals, including many insects, rodents, and bats can hear high-frequency ultrasonic sounds well beyond our own hearing range. Many other species have sensory systems that we lack completely, such as the magnetic sense of birds, turtles, and other animals, or the electric sense of many fish. These differences in sensory ability have a major bearing on the ways that animals behave and live in different environments, and also affect their evolution and ecology.
"What is it like to be a bat?", the philosopher Thomas Nagel famously asked concerning consciousness. For biologist Martin Stevens, the question forms the starting point of an exploration of animal senses. How indeed does a bat - or an owl, a bee, or a platypus - experience the world? Very differently to us humans, as we discover.
Many animals experience a world far richer in sight, sound, and smell and interact with each other in ways we simply don’t pick up, and which continue to surprise researchers. Who would imagine that rats and mice sing complex songs while courting; or that the humble dung beetle relies on light from the Milky Way above for guidance as it carries its precious cargo away from competitors? The world must show so much more colour to many birds, with four types of cones in their eyes instead of our three, and the ability to see into the ultraviolet. And that’s just considering the senses we share. What of those we have no inkling of - like the electric fields sensed by so many animals; or the magnetic maps used by migrating birds, and by sea turtles to find a current and return after many years to the shore where they hatched?
In this enthralling account, we learn not only of the wonder of animal senses, but how they work and how scientists go about investigating them. And, throughout, we consider how these senses came to be. For evolution is at the root of it all, as Stevens explains. Senses arose to enable animals to catch prey, to hide, and to mate more effectively, usually honed through fierce competition and arms races with predators. The result, over millions of years, is a wondrous panoply of ways of experiencing the world, against which our own senses often pale into insignificance.
8 pages, Audible Audio
Published August 3, 2021
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Displaying 1 - 15 of 15 reviews
October 8, 2021
One month ago today, Oct 8 2021, I went blind in one eye, today, I have my sight back. It's been a terrible month, and all the time, I thought it could be worse, and had what Helen Keller once said in my head, "Blindness cuts us off from things, but deafness cuts us from people." But that's not true anymore. Now we have the internet and hearing isn't necessary, but it is very hard to communicate effectively and participate in a site like this one, without sight. To Helen Keller, deafness was the worst affliction, but to me, it would be the loss of sight.
The book made me think. We might run things because of our big brains, but we aren't necessarily the best of anything physically and we don't obviously experience all the world has to offer, only having five senses is a real limitation. But it is a case of what you don't know you don't miss.
This book was published June 10th in the UK. The book details show it as Oct 1st which is the US edition. The editions should be combined so all the reviews apply to title, not edition. Since Goodreads Support took my librarian status away (I'd been one since 2008 and done more than 120,000 corrections to the data base) because I not-a-booked a spam Nigerian 'Dr Sebi' book which was, they said, against the ToS) and they operate a one strike and you're out policy, I can't combine the books, or correct the dates. The site may be American but when a book is published should be the first time, not when it was in the US.
____________________
This book is making me think, what other colours are there we cannot see or even imagine? How does the world look if you see polarised light. What if you weigh only an ounce or a kilo and think a journey of 10,000 miles is easy because you have internal GPS that works from the magnet pull of the Poles? Or you can work out where you are from the angle of the sun? Bees do that. I did that too, or attempted to with a sextant - it's difficult except in the calmest seas and when the sun is not obscured by clouds. Then there are maths, tables to look up and then you have to plot the course on a chart, yet there are creatures that automatically do all that... It amazes me.
____________________
All creatures interpret the world they see through their senses. We interpret them through our five, but there are many more senses an animal might have and they therefore see the world quite differently from us. Quite how can't really be known.
I've been reading about the mantis shrimp which are the most extraordinarily colourful animals I've ever seen. They also have the best sight in the world, most people have three colour receptors, but these shrimp have twelve. They are predators and very fierce and violent. A punch from one of them travels at 51 mph which if it misses the prey is ok, because the shock wave will kill them. That punch can break a man's finger!
This is a very interesting book, perhaps mostly in a magnetic sense, some of the creatures that possess it also have GPS. It doesn't matter if they are taken off course by hundreds of miles or the polarity of where they are (being experimented on) is changed, they make adjustments, that's a kind of GPS.
The book made me think. We might run things because of our big brains, but we aren't necessarily the best of anything physically and we don't obviously experience all the world has to offer, only having five senses is a real limitation. But it is a case of what you don't know you don't miss.
This book was published June 10th in the UK. The book details show it as Oct 1st which is the US edition. The editions should be combined so all the reviews apply to title, not edition. Since Goodreads Support took my librarian status away (I'd been one since 2008 and done more than 120,000 corrections to the data base) because I not-a-booked a spam Nigerian 'Dr Sebi' book which was, they said, against the ToS) and they operate a one strike and you're out policy, I can't combine the books, or correct the dates. The site may be American but when a book is published should be the first time, not when it was in the US.
____________________
This book is making me think, what other colours are there we cannot see or even imagine? How does the world look if you see polarised light. What if you weigh only an ounce or a kilo and think a journey of 10,000 miles is easy because you have internal GPS that works from the magnet pull of the Poles? Or you can work out where you are from the angle of the sun? Bees do that. I did that too, or attempted to with a sextant - it's difficult except in the calmest seas and when the sun is not obscured by clouds. Then there are maths, tables to look up and then you have to plot the course on a chart, yet there are creatures that automatically do all that... It amazes me.
____________________
All creatures interpret the world they see through their senses. We interpret them through our five, but there are many more senses an animal might have and they therefore see the world quite differently from us. Quite how can't really be known.
I've been reading about the mantis shrimp which are the most extraordinarily colourful animals I've ever seen. They also have the best sight in the world, most people have three colour receptors, but these shrimp have twelve. They are predators and very fierce and violent. A punch from one of them travels at 51 mph which if it misses the prey is ok, because the shock wave will kill them. That punch can break a man's finger!
This is a very interesting book, perhaps mostly in a magnetic sense, some of the creatures that possess it also have GPS. It doesn't matter if they are taken off course by hundreds of miles or the polarity of where they are (being experimented on) is changed, they make adjustments, that's a kind of GPS.
December 1, 2021
I've always been fascinated by animal senses, which in most of them, are far more acute and powerful than ours. Not to mention electric and magnetic ones, which humans do not possess at all.
The book is very well strctured, each chapter dealing with a sense, and plenty of examples of animals that have the keenest of it.
For those familiar with the subject, this is not a groundbreaking book. But it has some facts that I did not know about, such as that the sensory system of an animal can change during his life depending on the environment, or even vary during night and day, the energy used for that particular sense when not used being diverted to other.
I also knew that dogs' sense of smell is much more powerful than ours, but I did not know exactly how powerful. The olfactory membrane in a German Shepherd is 200 cm2 compared to humans' which is only 5.
There are many other subjects of interest which are tackled, and there is not a dull moment in the book. We have developed quite a few technological wonders based on animal senses and behaviour. We also have disturbed their senses to a quite high degree because of all forms of pollution, which is sad, to say the least.
All in all, a very interesting and well structured book, written on everyone's understanding.
The book is very well strctured, each chapter dealing with a sense, and plenty of examples of animals that have the keenest of it.
For those familiar with the subject, this is not a groundbreaking book. But it has some facts that I did not know about, such as that the sensory system of an animal can change during his life depending on the environment, or even vary during night and day, the energy used for that particular sense when not used being diverted to other.
I also knew that dogs' sense of smell is much more powerful than ours, but I did not know exactly how powerful. The olfactory membrane in a German Shepherd is 200 cm2 compared to humans' which is only 5.
There are many other subjects of interest which are tackled, and there is not a dull moment in the book. We have developed quite a few technological wonders based on animal senses and behaviour. We also have disturbed their senses to a quite high degree because of all forms of pollution, which is sad, to say the least.
All in all, a very interesting and well structured book, written on everyone's understanding.
August 9, 2021
An often-intriguing exploration of animal senses - both those familiar to us and (arguably most interestingly) those outside our human experience, such as the detection of electrical and magnetic fields. In each chapter, Martin Stevens gives us a wide range of examples of a particular sense in everything from spiders to bats, from naked mole rats to platypuses.
I have to confess I enjoy a good surprising science factoid - and there are a good number of these. I particularly liked the discovery that some bats' echolocation sounds are so loud that, if we were able to hear them they would be louder than a pneumatic drill (my comparison - he tells us the decibel level).
The book's only real failing is suffering from the biological science writing trap that was underlined by Rutherford's infamous dig 'all science is either physics or stamp collecting.' Although there are plenty of places where Stevens explores why something happens, there's also an awful lot of cataloguing here. So we discover that this species does this, while another species does that and so on. Occasionally I did suffer a little from being hit with too many examples and not enough narrative or explanatory science.
Having said that, there is much to engage the reader here. I particularly enjoyed the final two chapters on magnetic sensing and 'sensing in the Anthropocene.' The magnetic side was interesting because there are two competing theories as to how this is achieved, and there is often most to get your teeth into when there is scientific debate (the outcome between the two main theories here might be 'it's a bit of both'). The last chapter, on how humans have changed the environment in ways that affect animal senses (both in bad and good ways), is clearly covering a major interest for Stevens and is particularly fascinating.
All in all, an interesting and thoughtful contribution. It's a little confusing as Stevens had another book out less than four months before this one called Life in Colour - How Animals See the World which only covers the vision aspect of animal senses (I presume) - but the breadth of coverage of Secret Worlds gives it more of a substantial feel.
I have to confess I enjoy a good surprising science factoid - and there are a good number of these. I particularly liked the discovery that some bats' echolocation sounds are so loud that, if we were able to hear them they would be louder than a pneumatic drill (my comparison - he tells us the decibel level).
The book's only real failing is suffering from the biological science writing trap that was underlined by Rutherford's infamous dig 'all science is either physics or stamp collecting.' Although there are plenty of places where Stevens explores why something happens, there's also an awful lot of cataloguing here. So we discover that this species does this, while another species does that and so on. Occasionally I did suffer a little from being hit with too many examples and not enough narrative or explanatory science.
Having said that, there is much to engage the reader here. I particularly enjoyed the final two chapters on magnetic sensing and 'sensing in the Anthropocene.' The magnetic side was interesting because there are two competing theories as to how this is achieved, and there is often most to get your teeth into when there is scientific debate (the outcome between the two main theories here might be 'it's a bit of both'). The last chapter, on how humans have changed the environment in ways that affect animal senses (both in bad and good ways), is clearly covering a major interest for Stevens and is particularly fascinating.
All in all, an interesting and thoughtful contribution. It's a little confusing as Stevens had another book out less than four months before this one called Life in Colour - How Animals See the World which only covers the vision aspect of animal senses (I presume) - but the breadth of coverage of Secret Worlds gives it more of a substantial feel.
November 23, 2023
This is a fascinating and complex exploration of animal senses, how they function and the scientific investigations that led to these discoveries. The book is written in an academic style and includes chapters on: hearing, vision, electric attraction, touch, smell and magnetism. It concludes with a chapter on the impacts of the Anthropocene world on animal sensory functions.
A wide range of terrestrial and aquatic species are presented and examined in the book. Many of them have sensory capacities that are so different from (and superior to) human senses that it is difficult to comprehend the worlds these creatures inhabit. There are also more than two hundred references to research-based scientific publications that provide additional information for those who want to know more about any number of the topics covered in the text.
Overall, there is a rich treasure of information in this book but it is mostly intended for students of Sensory Ecology or others with a related academic background. Curious readers (like myself) who lack the appropriate academic prerequisites for a read of this nature may find the first three or four chapters somewhat overwhelming... I certainly did.
A wide range of terrestrial and aquatic species are presented and examined in the book. Many of them have sensory capacities that are so different from (and superior to) human senses that it is difficult to comprehend the worlds these creatures inhabit. There are also more than two hundred references to research-based scientific publications that provide additional information for those who want to know more about any number of the topics covered in the text.
Overall, there is a rich treasure of information in this book but it is mostly intended for students of Sensory Ecology or others with a related academic background. Curious readers (like myself) who lack the appropriate academic prerequisites for a read of this nature may find the first three or four chapters somewhat overwhelming... I certainly did.
April 11, 2023
A fascinating exploration of the senses of many different species and how blind we are to much that is going on in the world. For example, everyone knows that mice squeak, but much of their communication is in the ultrasonic, beyond human hearing. If we could hear them we would hear elaborate calls and mating songs and perhaps we would admire them like we do bird songs.
November 20, 2025
Martin Stevens' Secret Worlds is a genuinely immersive journey into perception itself. Rather than cataloguing facts, Stevens invites you to imagine what it's like to be a Caribbean spiny lobster navigating by magnetic fields, or a vampire bat hunting in absolute darkness using thermal pits, or a barn owl calculating the position of a mouse's whisper using microsecond timing differences. Opening with Thomas Nagel's famous question - "What is it like to be a bat?" - Stevens answers it not with abstract philosophy but with meticulous, empathetic science.
Stevens writes with genuine wonder. When he describes how a bat uses Doppler shift to detect a moth's velocity mid-flight, or how a dog's nose can determine odour location by having each nostril sample different air currents, you don't just learn the mechanism, you grasp something deeper: that the world these animals inhabit is fundamentally different from ours, equally sophisticated, equally real. The three-animal-per-chapter approach works beautifully.
Each chapter focuses on one sense - hearing, smell, vision, touch, electricity, magnetism and he chooses remarkable examples (barn owls, ants, four-eyed fish, star-nosed moles, electric fish) that reveal not just how senses work, but why they matter to survival.
What elevates this beyond a textbook is Stevens' attention to the cost-benefit evolution calculus. He discusses why blind cave fish lost their vision (saves 15% of energy), why lab fruit flies evolved smaller eyes, why rodents use ultrasonic frequencies we can't hear. This isn't dry - it's the story of how evolution ruthlessly optimizes for relevance. And his final chapters address our impact: how LED flicker affects animals, why horse racing fences painted orange are invisible to dichromatic horses, how pesticide pollution interferes with crayfish olfaction. Science with conscience.
Stevens succeeds at something profound: he trains you to see the world as fundamentally alien and miraculous.
A pigeon isn't stupid - it's navigating by magnetic fields you can't perceive.
A moth's hearing isn't inferior - it detects frequencies 15 times beyond your range.
Your dog isn't sniffing randomly - it's reading a chemical map of your emotional state.
By the end, you understand that calling any animal's sense "worse" than yours misses the entire point: senses are solutions to specific problems. The barn owl's hearing is perfection for hunting in darkness. The elephant's olfaction is perfection for tracking water across savanna. Your generalist senses are perfection for what you do.
Stevens writes with genuine wonder. When he describes how a bat uses Doppler shift to detect a moth's velocity mid-flight, or how a dog's nose can determine odour location by having each nostril sample different air currents, you don't just learn the mechanism, you grasp something deeper: that the world these animals inhabit is fundamentally different from ours, equally sophisticated, equally real. The three-animal-per-chapter approach works beautifully.
Each chapter focuses on one sense - hearing, smell, vision, touch, electricity, magnetism and he chooses remarkable examples (barn owls, ants, four-eyed fish, star-nosed moles, electric fish) that reveal not just how senses work, but why they matter to survival.
What elevates this beyond a textbook is Stevens' attention to the cost-benefit evolution calculus. He discusses why blind cave fish lost their vision (saves 15% of energy), why lab fruit flies evolved smaller eyes, why rodents use ultrasonic frequencies we can't hear. This isn't dry - it's the story of how evolution ruthlessly optimizes for relevance. And his final chapters address our impact: how LED flicker affects animals, why horse racing fences painted orange are invisible to dichromatic horses, how pesticide pollution interferes with crayfish olfaction. Science with conscience.
Stevens succeeds at something profound: he trains you to see the world as fundamentally alien and miraculous.
A pigeon isn't stupid - it's navigating by magnetic fields you can't perceive.
A moth's hearing isn't inferior - it detects frequencies 15 times beyond your range.
Your dog isn't sniffing randomly - it's reading a chemical map of your emotional state.
By the end, you understand that calling any animal's sense "worse" than yours misses the entire point: senses are solutions to specific problems. The barn owl's hearing is perfection for hunting in darkness. The elephant's olfaction is perfection for tracking water across savanna. Your generalist senses are perfection for what you do.
April 27, 2022
I particularly enjoyed the conclusion where he discussed how a better understanding of animal senses can help us in conservation initiatives.
January 31, 2025
A fun read. It was really cool to learn about the other senses and abilities that animals have to be able to navigate and make sense of the world.
And a little depressing because now I know that thermal vision and internal electromagnetic receptors exist in other organisms and I will never be able to have those abilities haha
Also left me amazed at how much more advanced dogs noses are than our own. What are they doing with all that information? Cool to think about
And a little depressing because now I know that thermal vision and internal electromagnetic receptors exist in other organisms and I will never be able to have those abilities haha
Also left me amazed at how much more advanced dogs noses are than our own. What are they doing with all that information? Cool to think about
February 24, 2023
This was well written. The science is relatively easy to follow, and interesting. The structure of the book is logical, and even though it's a non fiction book, it felt like I was taken on a journey. If you're interested in biology, ecology, and how humanity is affecting animal communication and navigation, I'd recommend reading Martin Stevens' research summary.
March 24, 2022
Good basic current review of animal senses. Very careful and thorough. And, alas, because of that, a bit boring. Too much detail, not enough summaries. Probably good as a supplemental text for Animal Behavior studies. I liked it but then, I'm biassed to animal behavior studies.
October 13, 2021
One of most interesting books I've read on animals.
March 23, 2022
A great read. All about the evolution of senses in the animal kingdom and how they use said senses.
November 17, 2022
This book is full of interesting information about senses animals use. Including some senses we humans do not have.
October 15, 2023
Like many other books of this genre, would've loved to see it on screen rather than read it. Also, the facts are just piled up one after the other without any link. Makes it difficult to imbibe.
November 16, 2023
Quite fascinating.
Displaying 1 - 15 of 15 reviews