Diving the Deep: A Book Review of Sy Montgomery’s The Soul of an Octopus

I saw my first octopus at the Oregon Coast Aquarium in Newport Beach, Oregon. The exhibit was tucked away inside a cave, meant to look like the inside of the ocean. The ten foot by ten foot window was mostly deserted. Other visitors cooed over the exhibits where otters were breaking open food against rocks and sea lions swam languidly in large circles, but as I peered inside of the cool, quiet enclosure, I struggled to see anything moving. And as I looked harder, I became more and more anxious. I desperately wanted to see an octopus.

Image for Kate Octopus Article 1.JPG

My family was itching to move on to the other exhibits, to the worlds of brightly colored sea anemones and deflated puffer fish, but I couldn’t leave. Something was compelling me to stay. Then, just as I stood up to walk away, I spotted him, a dark reddish-brown blob about two  feet in diameter, slowly undulating with the water. I was frozen and mesmerized, only pulled out of my trance by a small kid loudly asking their father where the octopus was. I pointed out the octopus to a few families before finally leaving the darkness of the cave and emerging again into the bright light.

Sy Montgomery opens her book The Soul of an Octopus by teaching the reader that the correct plural form of octopus is octopuses, not octopi. Octopus is a Greek word, while octopi has a Latin ending, making their joining incongruous, despite how widespread it is. Her book is a daring exploration into our conception of intelligence and consciousness through the lens of octopuses, and a piece that inspires the reader to find an octopus for themselves,  just as I did on my day at the aquarium.

Montgomery opens her book by revealing to the reader that she herself was an octopus novice: “I knew little about octopuses...But what I did know intrigued me. Here is an animal with venom like a snake, a beak like a parrot, and ink like an old-fashioned pen. It can weigh as much as a man and stretch as long as a car, yet it can pour its baggy, boneless body through an opening the size of an orange. It can change color and shape. It can taste with its skin. Most fascinating of all, I had read octopuses are smart.”

The reader is instantly captivated by the wonder and delight that Montgomery transfers from her interactions with these mysterious creatures to the prose she creates. Much like a kid who sees a dog for the first time, Montgomery’s interest is childlike and innocent, a true exploration into a topic solely for personal interest. The author mentions other projects that are also occupying her time, like a research trip to Namibia, making it clear that her interest in cephalopods, while in the end becoming a fascinating book, was more of a side interest. Her intense curiosity and fascination for the creatures inspires the reader to take a closer look, even for those not passionate about the ocean.


The author is able to describe sensory details using vivid imagery. When she meets her first octopus, Athena, she writes, “But Athena’s suction is gentle, though insistent. It pulls me like an alien’s kiss. Her melon-size head bobs to the surface...Its expression reminds me of the look in the eyes of paintings of Hindu gods and goddesses: serene, all-knowing, heavy with wisdom stretching back beyond time.” For Montgomery, the touch of an octopus is an otherworldly experience and a place where time seems to disappear. She attempts to share these feelings with the reader through compelling descriptions of both her physical and emotional experiences. She goes on to describe her interactions with the octopuses in the aquarium and the wild with the same attention to detail and awed reverence as this first intimate experience.

For those of you who have read my reviews before, you’ll know that I am a sucker for scientific details and explanations. Too often, Montgomery forgoes a more detailed scientific explanation in favor of a more literary approach to the topic. In fact, her discussion of the independent nature and movement of severed octopus arms barely merits a single paragraph, while the paragraph following it describing the beauty of an octopus sucker is almost four times as long. For a neuroscientist aching to understand the idea of dispersed consciousness, this disparity can be frustrating, highlighting that this is not a scientific text but a literary narrative of human contact with the marine world.

Because of this discrepancy, I took it upon myself to learn some of the science behind tentacles and octopus movement that the book failed to mention. About two thirds of the 500 million neurons in an octopus are located in its tentacles, according to an article from Current Biology. This localization pattern is unique to cephalopods and allows for almost autonomous movement of each octopus tentacle.  In the mid-20th century, researchers were able to determine that much of the processing of sensory input and coordination of motor output takes place in each tentacle due to the fact that there are so few connections between the neurons of the central nervous system and the neurons in the tentacles. In an octopus, the central nervous system is only involved in top level coordination and decision making. Octopuses lack any central representation of their arms, allowing them to perform unique, independent movements without having to centrally coordinate all eight arms and leading to observations that tentacles will continue to move for up to an hour after they are severed from the octopus’s body.

Sy Montgomery is a passionate writer with intimate knowledge of the octopus world. From quietly, desperately beautiful stories of a mother octopus caring for unfertilized eggs to tales of finding friendship and happiness from a joint love of octopuses, this book has (almost) everything an amateur lover of the sea could desire.