"Perfect for fans of The Soul of an Octopus and The Genius of Birds, this “masterpiece of science and nature writing” (The Washington Post) explores how we process the world around us through the lens of the incredible sensory capabilities of thirteen animals, revealing that we are not limited to merely five senses."

If you love reading and learning about animals you should read this book. I love learning about animals, and picking up any non-fiction book I can about them.

Great read, fascinating, educational and illuminating look into the sensory gifts of different animals including humans.

I really enjoyed this one! So many neat things to learn about animal intelligence and it really makes you think about the way we treat and interact with animals in the modern world. We can definitely learn a lot from the many cool, unexplored things we don't know about animals yet and how that can make us understand ourselves better. Higgins writes in a very gripping way, I flew through this in just a couple days. Would recommend to any nature or science readers I know!

On June 14, New York’s Supreme Court declared that an elephant is not a person.

Happy the elephant, the Guardian reported, will not be released from the Bronx zoo to a more spacious sanctuary through a habeas corpus proceeding, which is a way for people to challenge illegal confinement. The court said “granting legal personhood in a case like this would affect how humans interact with animals, according to the majority decision.”

Indeed. What they really mean, is that it would call into question our use of animals as objects to exploit.

Anyone who has seen how elephants mourn understands that elephants are persons. Moreover, we humans are animals, a fact so obvious that only willful ignorance can deny it.

So changing how we interact with animals might be a good thing, not only to save and protect other animals, but also to preserve the biosphere on which we depend.

This is very much the perspective that informs Jackie Higgins book, Sentient.

Higgins shows the evolutionary links between our own senses and those of animals—senses that encompass not only the five we are so familiar with, but up to seventeen more senses.

Sentient explores the scientific revolution stirring in the field of perception, showing that the extraordinary sensory powers of our animal friends can help us better understand the same powers that lie dormant within us.

Sentient is a celebration of sentience, specifically of humans. Primarily defined as one’s ability to experience the outside world, author Jackie Higgins uses various examples from the animal kingdom to lavish praise on this wonderful ability in humans compared to animals.

Peacock Mantis shrimp, for example, possess a highly developed sense of sight, being the only creatures able to grasp circularly polarized light. With no less than 12 different kinds of photoreceptors, their eyesight is much more developed compared to that of humans from an anatomical perspective. Most people are trichromats, having only three kinds of cones or receptors for color-vision: green, red and blue. A few special ones are tetrachromats, with an additional cone sensing shades between red and green. Physiologically however, human color vision was empirically found to be much more precise. ‘How is that possible?’ you might ask—it’s thanks to the highly developed human brain, capable of elaborating and integrating different external stimuli.

Throughout this fascinating book, Higgins, a graduate of Oxford University with an MA in zoology who has worked for Oxford Scientific Films for over a decade, displays her complex understanding of the non-human world. Moving on from the Peacock Mantis shrimp, she uses a litany of creatures to examine and worship the experiential world humans share or do not share with animals. We meet the spookfish and great gray owl; the star-nosed mole; the common vampire bat; the goliath catfish; the bloodhound; the giant peacock; the cheetah; the trashline orbweaver; the bar-tailed godwit; the common octopus; and the duck-billed platypus. With the platypus, for instance, we do not share the ability to sense electric fields.

We’re introduced to others engaged in (some might say ‘obsessed’) with these fascinating life forms. “‘My major research love in life is the mantis shrimp,’ confessed Justin Marshall, the professor in charge of the Sensory Neurobiology Group. He and his team are often seen swapping lab coats for snorkels and scuba gear to brave encounters with these plucky crustacea and keep their aquarium well stocked.” In some ways, Sentient is an informative and entertaining travelogue into worlds we’ll never visit, much like one of Sir David Attenborough’s documentaries (“A Life on Our Planet” or the most recent “Breaking Boundaries: The Science of Our Planet” come to mind). We are taken to the farthest reaches of the earth to meet and reflect upon the tiniest or most gigantic organisms mirroring the miracle of the world’s biodiversity and innate creativity.

As an author—and our guide to microscopic/macroscopic worlds—Higgins has an engaging prose style, educating us with her knowledge without boring us to death. Note her way of ‘teaching by showing,’ rather than simply ‘telling’ in this passage from a chapter about the bloodhound and our sense of smell:

Smell starts in dogs and humans when scent molecules are caught on an incoming tide of a breath, wash through to the depths of our nasal cavities, and reach the olfactory epithelium. This moist and mucous-coated membrane is crammed with olfactory neurons—the nose’s answer to the cones and rods of the eye, the hair cells of the ear, the mechanoreceptors or touch neurons of the skin, and the taste buds of the tongue. The business end of these long cells bears microscopic cilia that stick out and wave in the air current. These hairs are coated with olfactory receptor proteins that snare the passing scent molecules. The American neuroscientists Linda Buck and Richard Axel made the unanticipated and astonishing discovery—for which they were awarded the first ever Nobel Prize for olfaction in 2004—that mammals share an enormous family of genes that code for these receptor proteins. So the noses of dogs and humans are primed with the same kinds of scent-snagging biology.

Jackie Higgins
Photo by Alex Schneideman

Our ability as readers to be sentient certainly works to our advantage in gleaning the lessons that come from reading Sentient. Two important ones stood out to me: One is that evolution is a truly magnificent process, leaving one in awe in light of its intricacies and successes (as well as forgotten failures). In that regard, humans are no different from non-human animals in that we are all experiential creatures, treading life as we experience it and trying to survive and prosper.

The second lesson is in humility. Philosopher Thomas Nagel’s query of “What does it feel like to be a bat?” courses throughout the book, reminding us once again what Socrates tried to teach us centuries ago: We do not know what we do not know. We humans do not know the outer world we cannot experience. Technology helps a bit, for sure, but some parts of objective reality will forever remain uncharted territory for us, while being visible (or rather experienced) for others. Human abilities should then be praised without a doubt, but praise does not necessarily mean preferable, or more advanced, or superior. Humans and non-human animals alike have evolved to excel in their own habitat, made to respond to experiences sometimes only they are privy to.

So next time you feel like God has put you here to rule the animal kingdom, try to put yourself in the bloodhound’s paws—potentially there is a whole world out there that only he can experience.

Sigmund Freud reportedly thought that humans exchanged their sense of smell for superiority over animals. He was wrong. As with other senses, there is no ‘superior,’ only ‘different,’ and even that difference may be simply a matter of practice. As Higgins writes, “the dog beneath the skin exists within every one of us, waiting for our whistle.”

Sentient is a fun and illuminating read, highly recommended for those who cherish the winged or four-legged, or other creatures that walk, swim and fly among us. The book is even more highly recommended for those who don’t. —Zohar Lederman

Fascinating look into the sensory capabilities of humans and animals. A must-read for nature lovers!

"What animals can tell us about ourselves." That is what motivates Jackie Higgins as she seeks to illuminate the ability to see, feel, smell, hear, touch, desire, taste through an irresistible gallery of creatures, some of whom seem to be made wholly by imagination. The cheetah, for example, has a remarkable sense of balance that enables it to achieve astonishing speed. And the bloodhound, duh, well the nose knows. But what does the star-nosed mole have to tell us, or the spook fish or the hybrid pygmy shrimp? I sense some curiosity, hmmm, and this is the place to satisfy it.

In Sentient: How Animals Illuminate the Wonder of Our Human Senses, Jackie Higgins smoothly and successfully merges what could have been two popular science books — one on animal senses and one on human perception. Instead of separating the two subjects, here Higgins uses one as a vehicle for exploring the other. More precisely, by examining a dozen animal species and focusing on a single sensory trait they possess, Higgins casts a clarifying light on our own sensory abilities, including those we may not even be aware of.

Each chapter focuses on a single creature and sense, as follows
• Peacock Mantis Shrimp: color vision
• Great Gray Owl: hearing
• Star-Nosed Mole: touch
• Common Vampire Bat: pleasure/pain
• Goliath Catfish: taste
• Bloodhound: smell
• Giant Peacock of the Night: desire
• Cheetah: balance
• Trashline Orbweaver Spider: time
• Bar-Tailed Godwit (bird): direction
• Common Octopus: proprioception (sense of one’s own body)
• (An Afterword focuses on the duck-billed platypus)

The specific chapters follow an introduction that skims through a brief history of how we’ve viewed senses, noting that while most people think we have only five (taste, touch, sight, sense, smell), scientists will argue for a number more in the 20s or 30s, depending on which scientists you ask. And some, Higgins notes, will ‘argue it is folly to even try counting separate senses, as integration is about integrating information across them all, a fundamentally multisensory experience.”

The chapters themselves are concise, lucid, informative, and never fail to fascinate, even as Higgins goes well beyond simply describing the creature’s (and our) act of sensing but delves both into the mechanisms of the sense (which means getting into molecular biology, anatomy, and sometimes genetics, among other branches of science) and often how it arose, developed, and what evolutionary benefits it may be bestowed. While, as mentioned, Higgins mostly uses the animals as the vehicle for such exploration, much as Oliver Sacks once did (and Higgins in fact cites Sacks multiple times), she also brings in people who suffer from extremely rare genetic disorders or who have been the victims of traumatic injuries, using the way their senses were disrupted to illuminate the way a particular sense works. As when, for example, she tells the story of a man who lost his sense of his body and thus could not control his own limbs, though he could move them.

Two of the most interesting aspects of the book, for me at least, were Higgins’ chapters on the senses we’re less (or wholly) unaware of, and the ways in which she shows that humans, often contrary to our own beliefs, are actually pretty good at sensory perception, though we typically see ourselves as the “loser” when we compare ourselves to our animal brethren in terms of seeing or smelling.

For instance, she points to an experiment that shows that “a [human] rod photoreceptor cell can respond to a single photon and even resolve the statistics of photon numbers in weak flashes of light; that this can trigger a biochemical cascade . . . and, ultimately, this can lead to our perception of a single photon.” Granted, as the lead researcher said, “it’s more like a feeling of seeing something, rather than really seeing it … a feeling at the very threshold of your imagination — a feeling that there could have something, but you aren’t entirely sure;” but it’s still a pretty stunning result that, as Higgins puts it, “we can even detect, albeit vaguely, the individual elementary particles that make up our universe.” In similar veins, Higgins gives us experiments where humans can hear zero decibels (whispers are around 20), be trained to echolocate like bats, respond to a caress that only depresses the skin by five hundredths of a millimeter, and can track a 30-foot “twisting path marked by twine that had been dipped in the essential oil of chocolate” like a dog (in fact, humans outperform a number of animals in our sense of smell, including monkeys, otters, and rats).

As for the below-the-radar senses, these include not just the sense of body, which works more below are awareness for the obvious reason that it would be exhausting to have to pay such attention just to be able to stand (see the heartbreaking story referenced above Higgins includes regarding a man who must do just that), but also senses that were never considered part of the human realm: a sense of navigation and direction, a sense of time, and the like. These are relatively recent questions, some still being explored and debated (a raging debate over human pheromones for instance).

Sentience conveys everything clearly and concisely, in an engaging fashion, going into just the required amount of depth and detail so that the reader is left with a good understanding of the topic as opposed to being overwhelmed, and is also engaging and interesting enough that many readers will want to further explore the topic. Recommended.

This deserves lots of words, but I'll just use one: Excellent. I'm thinking that even if one has no interest in learning more about the animal kingdom that this will still be interesting. Recommended.

I really appreciate the free review copy!!

This book was so wonderful! The perfect non-fiction read ... relating to nature, and human form reminiscent of Diane Ackerman and her culmination of the delicate and vast depth of animals and humans. I hope to catch this again as it's released on audio for a wonderful an engaging listening experience. Thank you so much for an advanced copy of this book.

This was absolutely fascinating! Sooooo many senses! Even as a biology major with a number of animal behavior and physiology courses under my belt, I was able to learn so much about so many new friends! I'm so excited to get my hands on a physical copy to keep on my bookshelf in my future office.

Fascinating! A good, wide look at "the five senses" and beyond. Intriguing, keep-you-up-at-night accounts of both human and animal experiences of strange perceptions.

Sentient reports on scientific studies that describe our senses. It is not poetic or profound, nor does it offer insight into sentience, but it describes many sensory systems quite clearly and the chapters on mole rats and cheetahs approach considering the difference between perception and cognition and how many of the things we think we sense one way are actually informed my many senses. The book focuses on senses that humans have and uses non human sensory perception as extreme examples of our own experience. Rather than using non human senses that we do not share to define the ones we do.

I read this cover to cover in a few days, but suggest either reading one chapter at a time, or reading it interspersed with Diane Ackerman's Natural History of the Senses, a book referenced repeatedly in Sentient, because it is a poetic and insightful book on the same subject. Sentient focuses for long spans of pages on particular studies, quoting scientists and describing research without editorial or inspired language, while Ackerman jumps from example to idea to anecdote and personal experience and insight almost every sentence, leaving out the science. I gave each book a 3 out of 5 rating but might give them a 4 or 5 if I'd read them together. To add a third book to the mix try anything by Oliver Sacks, who is also repeatedly referred to in Sentient.

Although I didn't enjoy reading the book I enjoy the things I learned from the book.

This book offers so many insights about how to experience our senses for deeply. My favorite chapter was about cones in the eyes which see color and grayscale. I will definitely bring this book into inventory.